target/ppc: introduce ppc_maybe_interrupt

target/ppc: introduce ppc_maybe_interrupt

This new method will check if any pending interrupt was unmasked and
then call cpu_interrupt/cpu_reset_interrupt accordingly. Code that
raises/lowers or masks/unmasks interrupts should call this method to
keep CPU_INTERRUPT_HARD coherent with env->pending_interrupts.

Signed-off-by: Matheus Ferst <matheus.ferst@eldorado.org.br>
Reviewed-by: Daniel Henrique Barboza <danielhb413@gmail.com>
Message-Id: <20221021142156.4134411-2-matheus.ferst@eldorado.org.br>
Signed-off-by: Daniel Henrique Barboza <danielhb413@gmail.com>