powerpc: Add book3s hypervisor doorbell exception vectors

Directed Hypervisor Doorbell Interrupts come in at 0xe80 (or
0xc000000000004e80 if relocation on exceptions is enabled), so add
exception vectors at these locations.

If doorbell support is not compiled in we handle it as an
unknown_exception.

Signed-off-by: Ian Munsie <imunsie@au1.ibm.com>
Tested-by: Michael Neuling <mikey@neuling.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
diff --git a/arch/powerpc/include/asm/exception-64s.h b/arch/powerpc/include/asm/exception-64s.h
index ad708dd..9d5367e 100644
--- a/arch/powerpc/include/asm/exception-64s.h
+++ b/arch/powerpc/include/asm/exception-64s.h
@@ -305,6 +305,8 @@
 #define SOFTEN_VALUE_0x502	PACA_IRQ_EE
 #define SOFTEN_VALUE_0x900	PACA_IRQ_DEC
 #define SOFTEN_VALUE_0x982	PACA_IRQ_DEC
+#define SOFTEN_VALUE_0xe80	PACA_IRQ_DBELL
+#define SOFTEN_VALUE_0xe82	PACA_IRQ_DBELL
 
 #define __SOFTEN_TEST(h, vec)						\
 	lbz	r10,PACASOFTIRQEN(r13);					\