Convert CONFIG_SYS_I2C_MVTWSI to Kconfig

This converts the following to Kconfig:
   CONFIG_SYS_I2C_MVTWSI

Signed-off-by: Tom Rini <trini@konsulko.com>
diff --git a/configs/Marsboard_A10_defconfig b/configs/Marsboard_A10_defconfig
index a0aee66..e4ecb28 100644
--- a/configs/Marsboard_A10_defconfig
+++ b/configs/Marsboard_A10_defconfig
@@ -6,6 +6,7 @@
 CONFIG_AHCI=y
 # CONFIG_SYS_MALLOC_CLEAR_ON_INIT is not set
 CONFIG_SCSI_AHCI=y
+CONFIG_SYS_I2C_MVTWSI=y
 CONFIG_MII=y
 CONFIG_SUN4I_EMAC=y
 CONFIG_SUNXI_NO_PMIC=y