Input: synaptics-rmi4 - move IRQ handling to rmi_driver

The attn IRQ is related to the chip, rather than the transport, so move
all handling of interrupts to the core driver. This also makes sure that
there are no races between interrupts and availability of the resources
used by the core driver.

Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>