ARM: omap2plus_defconfig: Enable pcf857x

We have pcf857x at least several boards. Let's enable it
as a loadable module.

Cc: Brian Hutchinson <b.hutchman@gmail.com>
Signed-off-by: NTony Lindgren <tony@atomide.com>

arch/arm/configs/omap2plus_defconfig

@@ -207,6 +207,7 @@ CONFIG_SPI_TI_QSPI=m
 CONFIG_PINCTRL_SINGLE=y
 CONFIG_DEBUG_GPIO=y
 CONFIG_GPIO_SYSFS=y
+CONFIG_GPIO_PCF857X=m
 CONFIG_GPIO_TWL4030=y
 CONFIG_W1=m
 CONFIG_HDQ_MASTER_OMAP=m