sdmmc: complete abstract logic for Sdmmc1 power controller

libraries/libvapours/include/vapours/dd/dd_io_mapping.hpp

@@ -20,4 +20,7 @@ namespace ams::dd {
 
     uintptr_t QueryIoMapping(dd::PhysicalAddress phys_addr, size_t size);
 
+    u32 ReadIoRegister(dd::PhysicalAddress phys_addr);
+    void WriteIoRegister(dd::PhysicalAddress phys_addr, u32 value);
+
 }