sparc64: Add global PMU register dumping via sysrq.

Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/Documentation/sysrq.txt b/Documentation/sysrq.txt
index 642f844..2a4cdda 100644
--- a/Documentation/sysrq.txt
+++ b/Documentation/sysrq.txt
@@ -116,6 +116,7 @@
 'w'	- Dumps tasks that are in uninterruptable (blocked) state.
 
 'x'	- Used by xmon interface on ppc/powerpc platforms.
+          Show global PMU Registers on sparc64.
 
 'y'	- Show global CPU Registers [SPARC-64 specific]