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/net2big_v2_defconfig b/configs/net2big_v2_defconfig
index c1f8230..d8354f7 100644
--- a/configs/net2big_v2_defconfig
+++ b/configs/net2big_v2_defconfig
@@ -44,6 +44,7 @@
 CONFIG_NETCONSOLE=y
 CONFIG_DM=y
 CONFIG_SATA_MV=y
+CONFIG_SYS_I2C_MVTWSI=y
 CONFIG_SYS_I2C_EEPROM_ADDR=0x50
 # CONFIG_MMC is not set
 CONFIG_DM_SPI_FLASH=y