soc: qcom: rpmh-rsc: Avoid unnecessary checks on irq-done response

The RSC interrupt is issued only after the request is complete. For
fire-n-forget requests, the irq-done interrupt is sent after issuing the
RPMH request and for response-required request, the interrupt is
triggered only after all the requests are complete.

These unnecessary checks in the interrupt handler issues AHB reads from
a critical path. Lets remove them and clean up error handling in
rpmh_request data structures.

Co-developed-by: Lina Iyer <ilina@codeaurora.org>
Signed-off-by: Lina Iyer <ilina@codeaurora.org>
Signed-off-by: Abel Vesa <abel.vesa@linaro.org>
Signed-off-by: Bjorn Andersson <andersson@kernel.org>
Link: https://lore.kernel.org/r/20221116112246.2640648-2-abel.vesa@linaro.org