Input: Add pwm beeper driver

This patch adds a simple driver which allows to use pwm based beepers (for
example piezo elements) as a pcspkr-like device.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
diff --git a/drivers/input/misc/Makefile b/drivers/input/misc/Makefile
index 97b5dc3..19ccca7 100644
--- a/drivers/input/misc/Makefile
+++ b/drivers/input/misc/Makefile
@@ -29,6 +29,7 @@
 obj-$(CONFIG_INPUT_PCF8574)		+= pcf8574_keypad.o
 obj-$(CONFIG_INPUT_PCSPKR)		+= pcspkr.o
 obj-$(CONFIG_INPUT_POWERMATE)		+= powermate.o
+obj-$(CONFIG_INPUT_PWM_BEEPER)		+= pwm-beeper.o
 obj-$(CONFIG_INPUT_RB532_BUTTON)	+= rb532_button.o
 obj-$(CONFIG_INPUT_GPIO_ROTARY_ENCODER)	+= rotary_encoder.o
 obj-$(CONFIG_INPUT_SGI_BTNS)		+= sgi_btns.o