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/Empire_electronix_m712_defconfig b/configs/Empire_electronix_m712_defconfig
index 8482d8f..a795a4e 100644
--- a/configs/Empire_electronix_m712_defconfig
+++ b/configs/Empire_electronix_m712_defconfig
@@ -16,5 +16,6 @@
 CONFIG_VIDEO_LCD_BL_PWM="PB2"
 # CONFIG_SYS_MALLOC_CLEAR_ON_INIT is not set
 CONFIG_SPL_I2C=y
+CONFIG_SYS_I2C_MVTWSI=y
 CONFIG_CONS_INDEX=2
 CONFIG_USB_MUSB_HOST=y