AMU: Implement context save/restore for aarch32

Add amu_context_save() and amu_context_restore() functions for aarch32

Change-Id: I4df83d447adeaa9d9f203e16dc5a919ffc04d87a
Signed-off-by: Joel Hutton <joel.hutton@arm.com>
diff --git a/include/lib/aarch32/arch.h b/include/lib/aarch32/arch.h
index 630d3f2..3624cc6 100644
--- a/include/lib/aarch32/arch.h
+++ b/include/lib/aarch32/arch.h
@@ -544,7 +544,7 @@
 #define AMCNTENCLR0	p15, 0, c13, c2, 4
 #define AMCNTENSET0	p15, 0, c13, c2, 5
 #define AMCNTENCLR1	p15, 0, c13, c3, 0
-#define AMCNTENSET1	p15, 0, c13, c1, 1
+#define AMCNTENSET1	p15, 0, c13, c3, 1
 
 /* Activity Monitor Group 0 Event Counter Registers */
 #define AMEVCNTR00	p15, 0, c0