ARM: prima2_defconfig: enable build for misc input

we need INPUT_MISC to enable INPUT_SIRFSOC_ONKEY which is the onkey
driver for SiRFSoC platforms.
Signed-off-by: Barry Song <Baohua.Song@csr.com>

arch/arm/configs/prima2_defconfig

@@ -26,6 +26,7 @@ CONFIG_CHR_DEV_SG=y
 CONFIG_INPUT_EVDEV=y
 # CONFIG_INPUT_MOUSE is not set
 CONFIG_INPUT_TOUCHSCREEN=y
+CONFIG_INPUT_MISC=y
 CONFIG_SERIAL_SIRFSOC=y
 CONFIG_SERIAL_SIRFSOC_CONSOLE=y
 CONFIG_HW_RANDOM=y