GIC: Add API to set priority mask

API documentation updated.

Change-Id: I40feec1fe67a960d035061b54dd55610bc34ce1d
Signed-off-by: Jeenu Viswambharan <jeenu.viswambharan@arm.com>
diff --git a/plat/common/plat_gicv2.c b/plat/common/plat_gicv2.c
index 6460494..05fabca 100644
--- a/plat/common/plat_gicv2.c
+++ b/plat/common/plat_gicv2.c
@@ -272,3 +272,8 @@
 {
 	gicv2_clear_interrupt_pending(id);
 }
+
+unsigned int plat_ic_set_priority_mask(unsigned int mask)
+{
+	return gicv2_set_pmr(mask);
+}