sdmmc: Refactor again

- Refactor various variables and defines
- Removed Card/BGA and OEM ID info as they are static and useless
- Commented out bkops functions completely as not used
- Remove extra buf usage when there's already storage for storing that data
- Optimize various functions to save space
- Clean up useless or duplicate code

bdk/storage/sdmmc_driver.h

@@ -242,7 +242,7 @@ typedef struct _sdmmc_req_t
 	u32 num_sectors;
 	int is_write;
 	int is_multi_block;
-	int is_auto_cmd12;
+	int is_auto_stop_trn;
 } sdmmc_req_t;
 
 int  sdmmc_get_io_power(sdmmc_t *sdmmc);