soc: qcom: ipa: more IPA interrupt renames

Rename some functions to follow better naming conventions:
    ipa_add_interrupt_handler() -> ipa_interrupt_add()
    ipa_remove_interrupt_handler() -> ipa_interrupt_remove()
    ipa_handle_interrupt() -> ipa_interrupt_process()
    ipa_process_interrupts() -> ipa_interrupt_process_all()

Rename the IPA interrupt enumerated type to be ipa_interrupt.
Rename all of its symbolic values for consistency, each beginning
with "IPA_INTERRUPT_".

Rename the ipa_irq_mapping[] array to be ipa_interrupt_mapping[].

Signed-off-by: Alex Elder <elder@linaro.org>