ARM: imx: drop CONFIG_MMC_UNSAFE_RESUME from defconfig

Since 2501c917 (mmc: core: Use MMC_UNSAFE_RESUME as default behavior),
CONFIG_MMC_UNSAFE_RESUME is not available anymore.  Drop it from imx
defconfig.
Signed-off-by: Shawn Guo <shawn.guo@freescale.com>

arch/arm/configs/imx_v4_v5_defconfig

@@ -160,7 +160,6 @@ CONFIG_USB_CHIPIDEA_UDC=y
 CONFIG_USB_CHIPIDEA_HOST=y
 CONFIG_NOP_USB_XCEIV=y
 CONFIG_MMC=y
-CONFIG_MMC_UNSAFE_RESUME=y
 CONFIG_MMC_SDHCI=y
 CONFIG_MMC_SDHCI_PLTFM=y
 CONFIG_MMC_SDHCI_ESDHC_IMX=y

arch/arm/configs/imx_v6_v7_defconfig

@@ -221,7 +221,6 @@ CONFIG_USB_GADGET=y
 CONFIG_USB_ETH=m
 CONFIG_USB_MASS_STORAGE=m
 CONFIG_MMC=y
-CONFIG_MMC_UNSAFE_RESUME=y
 CONFIG_MMC_SDHCI=y
 CONFIG_MMC_SDHCI_PLTFM=y
 CONFIG_MMC_SDHCI_ESDHC_IMX=y

arch/arm/configs/mxs_defconfig

@@ -118,7 +118,6 @@ CONFIG_USB_GADGET=y
 CONFIG_USB_ETH=m
 CONFIG_USB_MASS_STORAGE=m
 CONFIG_MMC=y
-CONFIG_MMC_UNSAFE_RESUME=y
 CONFIG_MMC_MXS=y
 CONFIG_NEW_LEDS=y
 CONFIG_LEDS_CLASS=y