powerpc: Base support for exceptions using HSRR0/1

Pass the register type to the prolog, also provides alternate "HV"
version of hardware interrupt (0x500) and adjust LPES accordingly

We tag those interrupts by setting bit 0x2 in the trap number

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
diff --git a/arch/powerpc/kvm/book3s_rmhandlers.S b/arch/powerpc/kvm/book3s_rmhandlers.S
index b0ff5ff..046e1f3 100644
--- a/arch/powerpc/kvm/book3s_rmhandlers.S
+++ b/arch/powerpc/kvm/book3s_rmhandlers.S
@@ -112,6 +112,7 @@
 INTERRUPT_TRAMPOLINE	BOOK3S_INTERRUPT_DATA_STORAGE
 INTERRUPT_TRAMPOLINE	BOOK3S_INTERRUPT_INST_STORAGE
 INTERRUPT_TRAMPOLINE	BOOK3S_INTERRUPT_EXTERNAL
+INTERRUPT_TRAMPOLINE	BOOK3S_INTERRUPT_EXTERNAL_HV
 INTERRUPT_TRAMPOLINE	BOOK3S_INTERRUPT_ALIGNMENT
 INTERRUPT_TRAMPOLINE	BOOK3S_INTERRUPT_PROGRAM
 INTERRUPT_TRAMPOLINE	BOOK3S_INTERRUPT_FP_UNAVAIL