Workaround for Cortex A77 erratum 1800714

Cortex A77 erratum 1800714 is a Cat B erratum, present in older
revisions of the Cortex A77 processor core.  The workaround is to
set a bit in the ECTLR_EL1 system register, which disables allocation
of splintered pages in the L2 TLB.

Since this is the first errata workaround implemented for Cortex A77,
this patch also adds the required cortex_a77_reset_func in the file
lib/cpus/aarch64/cortex_a77.S.

This errata is explained in this SDEN:
https://static.docs.arm.com/101992/0010/Arm_Cortex_A77_MP074_Software_Developer_Errata_Notice_v10.pdf

Signed-off-by: John Powell <john.powell@arm.com>
Change-Id: I844de34ee1bd0268f80794e2d9542de2f30fd3ad
diff --git a/include/lib/cpus/aarch64/cortex_a77.h b/include/lib/cpus/aarch64/cortex_a77.h
index 0467ef3..bbd647c 100644
--- a/include/lib/cpus/aarch64/cortex_a77.h
+++ b/include/lib/cpus/aarch64/cortex_a77.h
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2018-2019, ARM Limited and Contributors. All rights reserved.
+ * Copyright (c) 2018-2020, ARM Limited and Contributors. All rights reserved.
  *
  * SPDX-License-Identifier: BSD-3-Clause
  */
@@ -16,6 +16,7 @@
  * CPU Extended Control register specific definitions.
  ******************************************************************************/
 #define CORTEX_A77_CPUECTLR_EL1				S3_0_C15_C1_4
+#define CORTEX_A77_CPUECTLR_EL1_BIT_53			(ULL(1) << 53)
 
 /*******************************************************************************
  * CPU Power Control register specific definitions.