fix(cpus): workaround for Cortex-A78 erratum 2742426

Cortex-A78 erratum 2742426 is a Cat B erratum that applies to
all revisions <= r1p2 and is still open.

The workaround is to set the CPUACTLR5_EL1[56:55] to 2'b01.

SDEN documentation:
https://developer.arm.com/documentation/SDEN1401784/latest

Signed-off-by: Bipin Ravi <bipin.ravi@arm.com>
Change-Id: I42506a87d41c9e2b30bc78c08d22f36e1f9635c1
diff --git a/include/lib/cpus/aarch64/cortex_a78.h b/include/lib/cpus/aarch64/cortex_a78.h
index fb325b6..66f565d 100644
--- a/include/lib/cpus/aarch64/cortex_a78.h
+++ b/include/lib/cpus/aarch64/cortex_a78.h
@@ -20,8 +20,8 @@
 #define CORTEX_A78_CPUECTLR_EL1				S3_0_C15_C1_4
 #define CORTEX_A78_CPUECTLR_EL1_BIT_8			(ULL(1) << 8)
 #define CORTEX_A78_CPUECTLR_EL1_PF_MODE_CNSRV		ULL(3)
-#define CPUECTLR_EL1_PF_MODE_LSB				U(6)
-#define CPUECTLR_EL1_PF_MODE_WIDTH				U(2)
+#define CPUECTLR_EL1_PF_MODE_LSB			U(6)
+#define CPUECTLR_EL1_PF_MODE_WIDTH			U(2)
 
 /*******************************************************************************
  * CPU Power Control register specific definitions
@@ -42,6 +42,8 @@
 
 #define CORTEX_A78_ACTLR3_EL1				S3_0_C15_C1_2
 
+#define CORTEX_A78_ACTLR5_EL1				S3_0_C15_C9_0
+
 /*******************************************************************************
  * CPU Activity Monitor Unit register specific definitions.
  ******************************************************************************/