ARM: ep93xx: add GPIO I2C to defconfig

Some of the EP93xx boards have I2C devices on bit-banged GPIO
I2C, so add this to the defconfig.
Reviewed-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

arch/arm/configs/ep93xx_defconfig

@@ -82,6 +82,7 @@ CONFIG_SERIAL_AMBA_PL010_CONSOLE=y
 # CONFIG_HW_RANDOM is not set
 CONFIG_I2C=y
 CONFIG_I2C_CHARDEV=y
+CONFIG_I2C_GPIO=y
 CONFIG_I2C_DEBUG_CORE=y
 CONFIG_I2C_DEBUG_ALGO=y
 CONFIG_I2C_DEBUG_BUS=y