Use __free(kfree) cleanup facility in matrix_keypad_parse_keymap() to
automatically free temporarily allocated memory.
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Link: https://lore.kernel.org/r/ZspoEPdTcH-hpciy@google.comSigned-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>