dm: mmc: Enable DM_MMC_OPS by default with DM_MMC

These two options go together and it is best to do the conversion in one
step. So enable DM_MMC_OPS by default if DM_MMC is enabled.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/configs/am335x_boneblack_vboot_defconfig b/configs/am335x_boneblack_vboot_defconfig
index 68769ea..c6ef650 100644
--- a/configs/am335x_boneblack_vboot_defconfig
+++ b/configs/am335x_boneblack_vboot_defconfig
@@ -43,6 +43,7 @@
 CONFIG_DFU_RAM=y
 CONFIG_DM_I2C=y
 CONFIG_DM_MMC=y
+# CONFIG_DM_MMC_OPS is not set
 CONFIG_SPI_FLASH=y
 CONFIG_SPI_FLASH_WINBOND=y
 CONFIG_DM_ETH=y