Avoid using DSi SD interface in NDS mode

Author: fincs

source/disc.c

@@ -86,10 +86,11 @@ const INTERFACE_ID _FAT_disc_interfaces[] = {
 
 /* ====================== NDS ====================== */
 #elif defined (NDS)
+#include <nds/system.h>
 #include <nds/arm9/dldi.h>
 
 static const DISC_INTERFACE* get_io_dsisd (void) {
-	return &__io_dsisd;
+	return isDSiMode() ? &__io_dsisd : NULL;
 }
 
 const INTERFACE_ID _FAT_disc_interfaces[] = {

source/libfat.c

@@ -154,6 +154,9 @@ bool fatInit (uint32_t cacheSize, bool setAsDefaultDevice) {
 		i++)
 	{
 		disc = _FAT_disc_interfaces[i].getInterface();
+		if (!disc) {
+			continue;
+		}
 		if (fatMount (_FAT_disc_interfaces[i].name, disc, 0, cacheSize, DEFAULT_SECTORS_PAGE)) {
 			// The first device to successfully mount is set as the default
 			if (defaultDevice < 0) {