Config symbols that select RFKILL need to depend on INPUT so that
undefined symbols are not used in the build.

This patch fixes the input_* symbols build errors.

(.text+0x174cdc): undefined reference to `input_unregister_device'
(.text+0x174d9f): undefined reference to `input_allocate_device'
(.text+0x174e2d): undefined reference to `input_register_device'
(.text+0x174e53): undefined reference to `input_free_device'
rt2x00rfkill.c:(.text+0x176dc4): undefined reference to `input_allocate_polled_device'
rt2x00rfkill.c:(.text+0x176e8b): undefined reference to `input_event'
rt2x00rfkill.c:(.text+0x176e9f): undefined reference to `input_event'
(.text+0x176eca): undefined reference to `input_unregister_polled_device'
(.text+0x176efc): undefined reference to `input_free_polled_device'
(.text+0x176f37): undefined reference to `input_free_polled_device'
(.text+0x176fd8): undefined reference to `input_register_polled_device'
(.text+0x1772c0): undefined reference to `led_classdev_resume'
(.text+0x1772d4): undefined reference to `led_classdev_resume'
(.text+0x1772e8): undefined reference to `led_classdev_resume'
(.text+0x17730a): undefined reference to `led_classdev_suspend'
(.text+0x17731e): undefined reference to `led_classdev_suspend'
(.text+0x17732f): undefined reference to `led_classdev_suspend'
rt2x00leds.c:(.text+0x177348): undefined reference to `led_classdev_unregister'
rt2x00leds.c:(.text+0x1773c0): undefined reference to `led_classdev_register'
rfkill-input.c:(.text+0x209e4c): undefined reference to `input_close_device'
rfkill-input.c:(.text+0x209e53): undefined reference to `input_unregister_handle'
rfkill-input.c:(.text+0x209ea1): undefined reference to `input_register_handle'
rfkill-input.c:(.text+0x209eae): undefined reference to `input_open_device'
rfkill-input.c:(.text+0x209ebb): undefined reference to `input_unregister_handle'
rfkill-input.c:(.init.text+0x17405): undefined reference to `input_register_handler'
rfkill-input.c:(.exit.text+0x194f): undefined reference to `input_unregister_handler'
make[1]: *** [vmlinux] Error 1

Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Acked-by: Ivo van Doorn <IvDoorn@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>