net: ipa: introduce a common microcontroller interrupt handler

The prototype for an IPA interrupt handler supplies the IPA
interrupt ID, so it's possible to use a single function to handle
any type of microcontroller interrupt.

Introduce ipa_uc_interrupt_handler(), which calls the event or the
response handler depending on the IRQ ID provided.  Register the new
function as the handler for both microcontroller IPA interrupt types.

The called functions don't use their "irq_id" arguments, so remove
them.

Signed-off-by: Alex Elder <elder@linaro.org>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>