fix(gicv3): update the affinity mask to 8 bit

The GIC ICC_SGI0R_EL1 register's affinity fields are 8bit wide for GIC
v3 and v4. Fix the SGIR_AFF_MASK variable accordingly.

Change-Id: I09f3fdd006708b40162776620f82abcfc6c3f782
Signed-off-by: Pranav Madhu <pranav.madhu@arm.com>

include/drivers/arm/gicv3.h

@@ -315,7 +315,7 @@
 #define SGIR_IRM_SHIFT			40
 #define SGIR_IRM_MASK			ULL(0x1)
 #define SGIR_AFF3_SHIFT			48
-#define SGIR_AFF_MASK			ULL(0xf)
+#define SGIR_AFF_MASK			ULL(0xff)
 
 #define SGIR_IRM_TO_AFF			U(0)