If the device is already in a runtime PM enabled state
pm_runtime_get_sync() will return 1, so a test for negative
value should be used to check for errors.

Fixes: f77621cc ("Input: omap-keypad - dynamically handle register offsets")
Signed-off-by: Miaoqian Lin <linmq006@gmail.com>
Link: https://lore.kernel.org/r/20220412070131.19848-1-linmq006@gmail.comSigned-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>