System: Move overlay checking to common

src/core/settings.h

@@ -143,6 +143,7 @@ struct Settings
   u8 cdrom_readahead_sectors = DEFAULT_CDROM_READAHEAD_SECTORS;
   bool cdrom_region_check = false;
   bool cdrom_load_image_to_ram = false;
+  bool cdrom_load_image_patches = false;
   bool cdrom_mute_cd_audio = false;
   u32 cdrom_read_speedup = 1;
   u32 cdrom_seek_speedup = 1;