EmbeddedPkg/MmcDxe: invoke SetIos() protocol method to set speed and width

Add the interface to change the bus width and speed.

By default, MMC is initialized with 1-bit mode and less than 400KHz bus
clock. It causes MMC working inefficiently.

Set I/O bus width on both MMC controller and EXTCSD. Otherwise, it may
cause unmatched failure case. And support more timing mode, high speed,
HS200 & HS400 mode.

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Haojian Zhuang <haojian.zhuang@linaro.org>
Tested-by: Ryan Harkin <ryan.harkin@linaro.org>
Reviewed-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>

EmbeddedPkg/Universal/MmcDxe/Mmc.h

@@ -55,6 +55,11 @@
 #define MMC_R0_STATE_TRAN       4
 #define MMC_R0_STATE_DATA       5
 
+#define EMMC_CMD6_ARG_ACCESS(x)             (((x) & 0x3) << 24)
+#define EMMC_CMD6_ARG_INDEX(x)              (((x) & 0xFF) << 16)
+#define EMMC_CMD6_ARG_VALUE(x)              (((x) & 0xFF) << 8)
+#define EMMC_CMD6_ARG_CMD_SET(x)            (((x) & 0x7) << 0)
+
 typedef enum {
   UNKNOWN_CARD,
   MMC_CARD,              //MMC card