Convert CONFIG_SYS_I2C_MXC et al to Kconfig

This converts the following to Kconfig:
   CONFIG_SYS_I2C_MXC
   CONFIG_SYS_I2C_MXC_I2C1
   CONFIG_SYS_I2C_MXC_I2C2
   CONFIG_SYS_I2C_MXC_I2C3
   CONFIG_SYS_I2C_MXC_I2C4

Signed-off-by: Tom Rini <trini@konsulko.com>
diff --git a/configs/usbarmory_defconfig b/configs/usbarmory_defconfig
index 5e581d9..427ea7b 100644
--- a/configs/usbarmory_defconfig
+++ b/configs/usbarmory_defconfig
@@ -7,6 +7,8 @@
 CONFIG_ENV_SIZE=0x2000
 CONFIG_ENV_OFFSET=0x60000
 CONFIG_TARGET_USBARMORY=y
+CONFIG_SYS_I2C_MXC_I2C1=y
+CONFIG_SYS_I2C_MXC_I2C2=y
 CONFIG_DM_GPIO=y
 CONFIG_DEFAULT_DEVICE_TREE="imx53-usbarmory"
 # CONFIG_CMD_BMODE is not set
@@ -24,6 +26,7 @@
 CONFIG_SYS_RELOC_GD_ENV_ADDR=y
 CONFIG_DM=y
 CONFIG_SYS_I2C_LEGACY=y
+CONFIG_SYS_I2C_MXC=y
 CONFIG_FSL_ESDHC_IMX=y
 CONFIG_MTD=y
 CONFIG_PINCTRL=y