[IA64] Enable percpu vector domain for IA64_GENERIC

Add per-CPU vector domain support for IA64_GENERIC. It is enabled by
adding the "vector=percpu" boot option.

Signed-off-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
Signed-off-by: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index 8363ad3..c48bc2e 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -1859,6 +1859,9 @@
 			vdso=1: enable VDSO (default)
 			vdso=0: disable VDSO mapping
 
+	vector=		[IA-64,SMP]
+			vector=percpu: enable percpu vector domain
+
 	video=		[FB] Frame buffer configuration
 			See Documentation/fb/modedb.txt.