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/Mele_M5_defconfig b/configs/Mele_M5_defconfig
index a6a0e6e..ac095f1 100644
--- a/configs/Mele_M5_defconfig
+++ b/configs/Mele_M5_defconfig
@@ -11,6 +11,7 @@
 # CONFIG_SYS_MALLOC_CLEAR_ON_INIT is not set
 CONFIG_SPL_I2C=y
 CONFIG_SCSI_AHCI=y
+CONFIG_SYS_I2C_MVTWSI=y
 CONFIG_PHY_REALTEK=y
 CONFIG_ETH_DESIGNWARE=y
 CONFIG_MII=y