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/ls1046aqds_defconfig b/configs/ls1046aqds_defconfig
index 1fe59ea..e2dc8db 100644
--- a/configs/ls1046aqds_defconfig
+++ b/configs/ls1046aqds_defconfig
@@ -6,6 +6,10 @@
 CONFIG_SYS_MEMTEST_END=0x9fffffff
 CONFIG_ENV_SIZE=0x20000
 CONFIG_ENV_SECT_SIZE=0x20000
+CONFIG_SYS_I2C_MXC_I2C1=y
+CONFIG_SYS_I2C_MXC_I2C2=y
+CONFIG_SYS_I2C_MXC_I2C3=y
+CONFIG_SYS_I2C_MXC_I2C4=y
 CONFIG_DM_GPIO=y
 CONFIG_DEFAULT_DEVICE_TREE="fsl-ls1046a-qds-duart"
 CONFIG_FSL_USE_PCA9547_MUX=y