Plat AXG: Fix PLAT_MAX_PWR_LVL value

This patch fixes AXG platform build error:
plat/amlogic/axg/axg_pm.c: In function 'axg_pwr_domain_off':
plat/amlogic/axg/axg_pm.c:124:43: error: array subscript 2
 is above array bounds of 'const plat_local_state_t[2]'
 {aka 'const unsigned char[2]'}
by changing PLAT_MAX_PWR_LVL from MPIDR_AFFLVL1 to MPIDR_AFFLVL2
in plat\amlogic\axg\include\platform_def.h.

Change-Id: I9a701e8f26231e62f844920aec5830664f3fb324
Signed-off-by: Alexei Fedorov <Alexei.Fedorov@arm.com>

plat/amlogic/axg/include/platform_def.h

 /*
- * Copyright (c) 2020, ARM Limited and Contributors. All rights reserved.
+ * Copyright (c) 2020, Arm Limited and Contributors. All rights reserved.
  *
  * SPDX-License-Identifier: BSD-3-Clause
  */
@@ -24,7 +24,7 @@
 
 #define AML_PRIMARY_CPU			U(0)
 
-#define PLAT_MAX_PWR_LVL		MPIDR_AFFLVL1
+#define PLAT_MAX_PWR_LVL		MPIDR_AFFLVL2
 #define PLAT_NUM_PWR_DOMAINS		(PLATFORM_CLUSTER_COUNT + \
 					 PLATFORM_CORE_COUNT)