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/vf610twr_defconfig b/configs/vf610twr_defconfig
index e5e0f51..f1693e8 100644
--- a/configs/vf610twr_defconfig
+++ b/configs/vf610twr_defconfig
@@ -7,6 +7,8 @@
 CONFIG_SYS_MEMTEST_END=0x87c00000
 CONFIG_ENV_SIZE=0x2000
 CONFIG_ENV_OFFSET=0xC0000
+CONFIG_SYS_I2C_MXC_I2C1=y
+CONFIG_SYS_I2C_MXC_I2C2=y
 CONFIG_DM_GPIO=y
 CONFIG_DEFAULT_DEVICE_TREE="vf610-twr"
 CONFIG_SYS_EXTRA_OPTIONS="IMX_CONFIG=board/freescale/vf610twr/imximage.cfg"
@@ -38,6 +40,7 @@
 CONFIG_DM=y
 CONFIG_VYBRID_GPIO=y
 CONFIG_SYS_I2C_LEGACY=y
+CONFIG_SYS_I2C_MXC=y
 CONFIG_FSL_ESDHC_IMX=y
 CONFIG_MTD=y
 CONFIG_NAND_VF610_NFC=y