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/mx6ulz_14x14_evk_defconfig b/configs/mx6ulz_14x14_evk_defconfig
index 23c8210..a3cd54f 100644
--- a/configs/mx6ulz_14x14_evk_defconfig
+++ b/configs/mx6ulz_14x14_evk_defconfig
@@ -35,6 +35,7 @@
 CONFIG_BOUNCE_BUFFER=y
 CONFIG_DM_74X164=y
 CONFIG_DM_I2C=y
+CONFIG_SYS_I2C_MXC=y
 CONFIG_FSL_ESDHC_IMX=y
 CONFIG_MTD=y
 CONFIG_DM_SPI_FLASH=y