exo: read first two sd card sectors in mariko_fatal

exosphere/mariko_fatal/source/fatal_sdmmc.hpp

@@ -19,5 +19,7 @@
 namespace ams::secmon::fatal {
 
     Result InitializeSdCard();
+    Result CheckSdCardConnection(sdmmc::SpeedMode *out_sm, sdmmc::BusWidth *out_bw);
+    Result ReadSdCard(void *dst, size_t size, size_t sector_index, size_t sector_count);
 
 }