Convert CONFIG_SYS_I2C_SPEED et al to Kconfig

This converts the following to Kconfig:
   CONFIG_SYS_I2C_SPEED
   CONFIG_SYS_I2C_SLAVE

Signed-off-by: Tom Rini <trini@konsulko.com>
diff --git a/configs/UTOO_P66_defconfig b/configs/UTOO_P66_defconfig
index 0dfbeed..b572807 100644
--- a/configs/UTOO_P66_defconfig
+++ b/configs/UTOO_P66_defconfig
@@ -25,6 +25,8 @@
 CONFIG_SYS_I2C_SOFT_SPEED=50000
 CONFIG_SYS_I2C_SOFT_SLAVE=0x00
 CONFIG_SYS_I2C_MVTWSI=y
+CONFIG_SYS_I2C_SLAVE=0x7f
+CONFIG_SYS_I2C_SPEED=400000
 # CONFIG_REQUIRE_SERIAL_CONSOLE is not set
 CONFIG_CONS_INDEX=2
 CONFIG_USB_MUSB_HOST=y