input: keychord: Add keychord driver

This driver allows userspace to receive notification when client
specified key combinations are pressed.
The client opens /dev/keychord and writes a list of keychords
for the driver to monitor.
The client then reads or polls /dev/keychord for notifications.
A client specified ID for the keychord is returned from read()
when a keychord press is detected.

Signed-off-by: Mike Lockwood <lockwood@android.com>

keychord: fix to build without CONFIG_PREEMPT

Change-Id: I911f13aeda4224b6fa57863bc7e8972fec8837fb
diff --git a/drivers/input/misc/Makefile b/drivers/input/misc/Makefile
index 75946ee..eb73834 100644
--- a/drivers/input/misc/Makefile
+++ b/drivers/input/misc/Makefile
@@ -25,6 +25,7 @@
 obj-$(CONFIG_INPUT_GPIO)		+= gpio_event.o gpio_matrix.o gpio_input.o gpio_output.o gpio_axis.o
 obj-$(CONFIG_HP_SDC_RTC)		+= hp_sdc_rtc.o
 obj-$(CONFIG_INPUT_IXP4XX_BEEPER)	+= ixp4xx-beeper.o
+obj-$(CONFIG_INPUT_KEYCHORD)		+= keychord.o
 obj-$(CONFIG_INPUT_KEYSPAN_REMOTE)	+= keyspan_remote.o
 obj-$(CONFIG_INPUT_M68K_BEEP)		+= m68kspkr.o
 obj-$(CONFIG_INPUT_MAX8925_ONKEY)	+= max8925_onkey.o