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/pico-imx7d_bl33_defconfig b/configs/pico-imx7d_bl33_defconfig
index 33fc277..495ff84 100644
--- a/configs/pico-imx7d_bl33_defconfig
+++ b/configs/pico-imx7d_bl33_defconfig
@@ -7,6 +7,10 @@
 CONFIG_SYS_MEMTEST_END=0xa0000000
 CONFIG_ENV_SIZE=0x2000
 CONFIG_ENV_OFFSET=0xC0000
+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="imx7d-pico-pi"
 CONFIG_TARGET_PICO_IMX7D=y
@@ -50,6 +54,7 @@
 CONFIG_DFU_MMC=y
 CONFIG_SYS_I2C_LEGACY=y
 CONFIG_SPL_SYS_I2C_LEGACY=y
+CONFIG_SYS_I2C_MXC=y
 CONFIG_FSL_USDHC=y
 CONFIG_MTD=y
 CONFIG_PHYLIB=y