Fix ability to set SFX audio without console reboot (#118)

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## Description
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Allow realtime setting changes for SFX in menu.
Add note that the PAL60 setting still requires a reboot.

## Motivation and Context
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issue here -->
The sfx setting previously required a flashcart reboot.

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## Types of changes
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- [x] Improvement (non-breaking change that adds a new feature)
- [ ] Bug fix (fixes an issue)
- [ ] Breaking change (breaking change)
- [ ] Config and build (change in the configuration and build system,
has no impact on code or features)

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- [ ] All new and existing tests passed.

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src/menu/menu.c

@@ -119,8 +119,9 @@ static void menu_init (boot_params_t *boot_params) {
         __boot_tvtype = TV_NTSC;
     }
 
+    sound_init_sfx();
     if (menu->settings.sound_enabled) {
-        sound_init_sfx();
+        sound_use_sfx(true);
     }
 
     display_init(RESOLUTION_640x480, DEPTH_16_BPP, 2, GAMMA_NONE, FILTERS_DISABLED);

src/menu/sound.c

@@ -50,6 +50,14 @@ void sound_init_sfx (void) {
     sfx_enabled = true;
 }
 
+void sound_use_sfx(bool state) {
+    if (state) {
+        sfx_enabled = true;
+    }
+    else {
+        sfx_enabled = false;
+    }
+}
 
 void sound_play_effect(sound_effect_t sfx) {
     if(sfx_enabled) {

src/menu/sound.h

@@ -7,6 +7,7 @@
 #ifndef SOUND_H__
 #define SOUND_H__
 
+#include <stdbool.h>
 
 #define SOUND_MP3_PLAYER_CHANNEL    (0)
 #define SOUND_SFX_CHANNEL           (2)
@@ -23,6 +24,7 @@ typedef enum {
 void sound_init_default (void);
 void sound_init_mp3_playback (void);
 void sound_init_sfx (void);
+void sound_use_sfx(bool);
 void sound_play_effect(sound_effect_t sfx);
 void sound_deinit (void);
 void sound_poll (void);

src/menu/views/settings_editor.c

@@ -30,6 +30,7 @@ static void set_use_saves_folder_type (menu_t *menu, void *arg) {
 
 static void set_sound_enabled_type (menu_t *menu, void *arg) {
     menu->settings.sound_enabled = (bool) (arg);
+    sound_use_sfx(menu->settings.sound_enabled);
     settings_save(&menu->settings);
 }
 
@@ -134,19 +135,19 @@ static void draw (menu_t *menu, surface_t *d) {
     component_main_text_draw(
         ALIGN_LEFT, VALIGN_TOP,
         "\n\n"
-        "     Default Directory : %s\n\n"
-        "To change the menu settings, press 'A'.\n\n"
-        "     PAL60 Mode        : %s\n"
+        "  Default Directory : %s\n\n"
+        "To change the following menu settings, press 'A':\n"
+        "*    PAL60 Mode        : %s\n"
         "     Show Hidden Files : %s\n"
         "     Use Saves folder  : %s\n"
-        "*    Sound Effects     : %s\n"
+        "     Sound Effects     : %s\n"
 #ifdef BETA_SETTINGS
         "     Background Music  : %s\n"
         "     Rumble Feedback   : %s\n"
 #endif
-        "\n\n"
         "Note: Certain settings have the following caveats:\n\n"
         "*    Requires a flashcart reboot.\n",
+        "\n",
         menu->settings.default_directory,
         format_switch(menu->settings.pal60_enabled),
         format_switch(menu->settings.show_protected_entries),