Input: ims-pcu - switch to using cleanup functions

Start using __free() and guard() primitives to simplify the code
and error handling.

Link: https://lore.kernel.org/r/20240610041813.722445-2-dmitry.torokhov@gmail.com


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