errata: workaround for Neoverse N2 erratum 2189731

Neoverse N2 erratum 2189731 is a Cat B erratum that applies to
revision r0p0 and is still open. The workaround is to set
CPUACTLR5_EL1[44] to 1 which will cause the CPP instruction to
invalidate the hardware prefetcher state trained from any EL.

SDEN can be found here:
https://developer.arm.com/documentation/SDEN1982442/latest

Signed-off-by: Bipin Ravi <bipin.ravi@arm.com>
Change-Id: Iddc6a59adf9fa3cab560c46f2133e1f5a8b3ad03
diff --git a/include/lib/cpus/aarch64/neoverse_n2.h b/include/lib/cpus/aarch64/neoverse_n2.h
index 68f6a40..948f965 100644
--- a/include/lib/cpus/aarch64/neoverse_n2.h
+++ b/include/lib/cpus/aarch64/neoverse_n2.h
@@ -35,4 +35,10 @@
 #define NEOVERSE_N2_CPUACTLR2_EL1		S3_0_C15_C1_1
 #define NEOVERSE_N2_CPUACTLR2_EL1_BIT_2		(ULL(1) << 2)
 
+/*******************************************************************************
+ * CPU Auxiliary Control register 5 specific definitions.
+ ******************************************************************************/
+#define NEOVERSE_N2_CPUACTLR5_EL1		S3_0_C15_C8_0
+#define NEOVERSE_N2_CPUACTLR5_EL1_BIT_44	(ULL(1) << 44)
+
 #endif /* NEOVERSE_N2_H */