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/pinecube_defconfig b/configs/pinecube_defconfig
index abe2997..c54958e 100644
--- a/configs/pinecube_defconfig
+++ b/configs/pinecube_defconfig
@@ -8,6 +8,7 @@
 CONFIG_DRAM_ODT_EN=y
 CONFIG_I2C0_ENABLE=y
 CONFIG_SPL_I2C=y
+CONFIG_SYS_I2C_MVTWSI=y
 # CONFIG_NETDEVICES is not set
 CONFIG_AXP209_POWER=y
 CONFIG_AXP_DCDC2_VOLT=1250