Input: spear-keyboard - improve build coverage using COMPILE_TEST

Used to test the PM changes.

Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Link: https://lore.kernel.org/r/20221204180841.2211588-29-jic23@kernel.org


Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>