board: cm_fx6: convert to DM_I2C

Conversion to DM_I2C is mandatory, enable DM_I2C to fix board
removal warning. Convert EEPROM access to use DM_I2C API.

Signed-off-by: Anatolij Gustschin <agust@denx.de>
Reviewed-by: Fabio Estevam <festevam@gmail.com>
diff --git a/configs/cm_fx6_defconfig b/configs/cm_fx6_defconfig
index 386616c..81a39f7 100644
--- a/configs/cm_fx6_defconfig
+++ b/configs/cm_fx6_defconfig
@@ -80,7 +80,7 @@
 CONFIG_DWC_AHSATA=y
 # CONFIG_DWC_AHSATA_AHCI is not set
 CONFIG_LBA48=y
-CONFIG_SYS_I2C_LEGACY=y
+CONFIG_DM_I2C=y
 CONFIG_SPL_SYS_I2C_LEGACY=y
 CONFIG_SYS_I2C_MXC=y
 CONFIG_SYS_MXC_I2C3_SPEED=400000