Input: synaptics-rmi4 - do not delete interrupt memory too early

We want to free memory reserved for interrupt mask handling only after we
free functions, as function drivers might want to mask interrupts. This is
needed for the followup patch to the F03 that would implement unmasking and
masking interrupts from the serio pass-through port open() and close()
methods.

Cc: stable@vger.kernel.org
Reviewed-by: Lyude Paul <lyude@redhat.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>