target/ppc: define PPC_INTERRUPT_* values directly

target/ppc: define PPC_INTERRUPT_* values directly

This enum defines the bit positions in env->pending_interrupts for each
interrupt. However, except for the comparison in kvmppc_set_interrupt,
the values are always used as (1 << PPC_INTERRUPT_*). Define them
directly like that to save some clutter. No functional change intended.

Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Matheus Ferst <matheus.ferst@eldorado.org.br>
Message-Id: <20221011204829.1641124-2-matheus.ferst@eldorado.org.br>
Signed-off-by: Daniel Henrique Barboza <danielhb413@gmail.com>