mmc: dw_mmc: support 8-bit buswidth

This patch adds support for 8-bit buswidth.
dw_mmc can use 8-bit buswidth and set to CTYPE_8BIT in card-type register.

Signed-off-by: Jaehoon Chung <[e-mail]>
Signed-off-by: Kyungmin Park <[e-mail]>
Acked-by: Will Newton <[e-mail]>
Signed-off-by: Chris Ball <[e-mail]>

drivers/mmc/host/dw_mmc.c

···
 	case MMC_BUS_WIDTH_4:
 		slot->ctype = SDMMC_CTYPE_4BIT;
 		break;
+	case MMC_BUS_WIDTH_8:
+		slot->ctype = SDMMC_CTYPE_8BIT;
+		break;
 	}
 
 	if (ios->clock) {