powerpc/pseries: Export data from new hcall H_EM_GET_PARMS

Add support for H_EM_GET_PARMS hcall that will return data
related to power modes from the platform.  Export the data
directly to user space for administrative tools to interpret
and use.

cat /proc/powerpc/lparcfg will export power mode data

Signed-off-by: Vaidyanathan Srinivasan <svaidy@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
diff --git a/arch/powerpc/include/asm/hvcall.h b/arch/powerpc/include/asm/hvcall.h
index f027581..ebe7493 100644
--- a/arch/powerpc/include/asm/hvcall.h
+++ b/arch/powerpc/include/asm/hvcall.h
@@ -228,6 +228,7 @@
 #define H_JOIN			0x298
 #define H_VASI_STATE            0x2A4
 #define H_ENABLE_CRQ		0x2B0
+#define H_GET_EM_PARMS		0x2B8
 #define H_SET_MPP		0x2D0
 #define H_GET_MPP		0x2D4
 #define MAX_HCALL_OPCODE	H_GET_MPP