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/MK808C_defconfig b/configs/MK808C_defconfig
index 6f003f8..3456258 100644
--- a/configs/MK808C_defconfig
+++ b/configs/MK808C_defconfig
@@ -6,5 +6,6 @@
 CONFIG_DRAM_CLK=384
 # CONFIG_SYS_MALLOC_CLEAR_ON_INIT is not set
 CONFIG_SPL_I2C=y
+CONFIG_SYS_I2C_MVTWSI=y
 CONFIG_USB_EHCI_HCD=y
 CONFIG_USB_OHCI_HCD=y