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/pov_protab2_ips9_defconfig b/configs/pov_protab2_ips9_defconfig
index 1f9b3e0..0f0cf27 100644
--- a/configs/pov_protab2_ips9_defconfig
+++ b/configs/pov_protab2_ips9_defconfig
@@ -15,4 +15,5 @@
 CONFIG_VIDEO_LCD_PANEL_LVDS=y
 # CONFIG_SYS_MALLOC_CLEAR_ON_INIT is not set
 CONFIG_SPL_I2C=y
+CONFIG_SYS_I2C_MVTWSI=y
 CONFIG_USB_MUSB_HOST=y