Input: st-keyscan - improve probe error handling

Use dev_err_probe() for devm_clk_get() to prevent log spam when probe
returns -EPROBE_DEFER.
Drop the redundant error message after devm_request_irq(), since the
helper already reports request failures internally.
Return the original error from platform_get_irq() instead of replacing
it with -EINVAL.

Signed-off-by: bui duc phuc <phucduc.bui@gmail.com>
Link: https://patch.msgid.link/20260727101125.28291-2-phucduc.bui@gmail.com
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>