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/mx6sabresd_defconfig b/configs/mx6sabresd_defconfig
index 7a16152..533cf29 100644
--- a/configs/mx6sabresd_defconfig
+++ b/configs/mx6sabresd_defconfig
@@ -10,6 +10,9 @@
 CONFIG_ENV_OFFSET=0xC0000
 CONFIG_MX6QDL=y
 CONFIG_TARGET_MX6SABRESD=y
+CONFIG_SYS_I2C_MXC_I2C1=y
+CONFIG_SYS_I2C_MXC_I2C2=y
+CONFIG_SYS_I2C_MXC_I2C3=y
 CONFIG_DM_GPIO=y
 CONFIG_DEFAULT_DEVICE_TREE="imx6q-sabresd"
 CONFIG_SPL_TEXT_BASE=0x00908000
@@ -79,6 +82,7 @@
 CONFIG_FASTBOOT_FLASH_MMC_DEV=2
 CONFIG_SYS_I2C_LEGACY=y
 CONFIG_SPL_SYS_I2C_LEGACY=y
+CONFIG_SYS_I2C_MXC=y
 CONFIG_SUPPORT_EMMC_BOOT=y
 CONFIG_FSL_USDHC=y
 CONFIG_MTD=y