powerpc/irq: Replace #ifdefs by IS_ENABLED()

Replace
  #ifdef CONFIG_PPC_IRQ_SOFT_MASK_DEBUG and
  #ifdef CONFIG_PERF_EVENTS
by IS_ENABLED() in hw_irq.h and plpar_wrappers.h

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/c1ded642f8d9002767f8fed48ed6d1e76254ed73.1652862729.git.christophe.leroy@csgroup.eu