imx: Fix regression with CONFIG_DM_MMC=y

When CONFIG_DM_MMC=y, CONFIG_BLK should be selected, otherwise the
SD/eMMC card cannot be used.

Also, select CONFIG_DM_USB=y when CONFIG_USB=y to avoid build failure.

Tested on mx6slevk, mx7dsabresd and mx6ullevk.

Signed-off-by: Fabio Estevam <fabio.estevam@nxp.com>
Reviewed-by: Jaehoon Chung <jh80.chung@samsung.com>
Tested-by: Adam Ford <aford173@gmail.com>
Tested-by: Sébastien Szymanski <sebastien.szymanski@armadeus.com>
Tested-by: Jagan Teki <jagan@openedev.com>
Reviewed-by: Jagan Teki <jagan@openedev.com>
diff --git a/configs/mx6slevk_spinor_defconfig b/configs/mx6slevk_spinor_defconfig
index 020d19f..4b9c04e 100644
--- a/configs/mx6slevk_spinor_defconfig
+++ b/configs/mx6slevk_spinor_defconfig
@@ -28,7 +28,6 @@
 CONFIG_OF_CONTROL=y
 CONFIG_ENV_IS_IN_SPI_FLASH=y
 CONFIG_DM=y
-# CONFIG_BLK is not set
 CONFIG_DM_GPIO=y
 CONFIG_DM_I2C=y
 CONFIG_DM_MMC=y
@@ -45,6 +44,7 @@
 CONFIG_DM_REGULATOR_GPIO=y
 CONFIG_DM_THERMAL=y
 CONFIG_USB=y
+CONFIG_DM_USB=y
 CONFIG_USB_STORAGE=y
 CONFIG_USB_HOST_ETHER=y
 CONFIG_USB_ETHER_ASIX=y