Update motorola_power to irq-generic interrupt management

- Add support to the BSP to enable irq-generic management

- Update the powerpc shared irq code to support irq-generic. This
  is an opt in option for existing powerpc bsps. This change
  should be simpler now

- Fix a number of issues in ISA IRQ controller handling by porting
  fixes from the i386 (PC) BSP

Closes #4238
Closes #4239

spec/build/bsps/powerpc/motorola_powerpc/grp.yml

@@ -10,7 +10,7 @@ links:
 - role: build-dependency
   uid: ../../obj
 - role: build-dependency
-  uid: ../../objirqdflt
+  uid: ../../objirq
 - role: build-dependency
   uid: ../crti
 - role: build-dependency

spec/build/bsps/powerpc/motorola_powerpc/obj.yml

@@ -39,7 +39,7 @@ source:
 - bsps/powerpc/shared/irq/irq_init.c
 - bsps/powerpc/shared/irq/openpic.c
 - bsps/powerpc/shared/irq/openpic_i8259_irq.c
-- bsps/powerpc/shared/irq/ppc-irq-legacy.c
+- bsps/powerpc/shared/irq/ppc-irq-generic.c
 - bsps/powerpc/shared/mmu/bat.c
 - bsps/powerpc/shared/mmu/mmuAsm.S
 - bsps/powerpc/shared/mmu/pte121.c
@@ -57,5 +57,6 @@ source:
 - bsps/powerpc/shared/start/zerobss.c
 - bsps/shared/dev/getentropy/getentropy-cpucounter.c
 - bsps/shared/dev/rtc/rtc-support.c
+- bsps/shared/irq/irq-default-handler.c
 - bsps/shared/start/bspfatal-default.c
 type: build