Define registers for FEAT_RNG support

Add ISAR0 feature register read helper, location
of FEAT_RNG bits, feature support helper and the
rndr/rndrrs register read helpers.

Signed-off-by: Tomas Pilar <tomas@nuviainc.com>
Change-Id: I2a785a36f62a917548e55892ce92fa8b72fcb99d
diff --git a/include/arch/aarch64/arch.h b/include/arch/aarch64/arch.h
index 09e598a..2cdc7b2 100644
--- a/include/arch/aarch64/arch.h
+++ b/include/arch/aarch64/arch.h
@@ -193,6 +193,10 @@
 #define ID_AA64DFR0_MTPMU_MASK		ULL(0xf)
 #define ID_AA64DFR0_MTPMU_SUPPORTED	ULL(1)
 
+/* ID_AA64ISAR0_EL1 definitions */
+#define ID_AA64ISAR0_RNDR_SHIFT U(60)
+#define ID_AA64ISAR0_RNDR_MASK  ULL(0xf)
+
 /* ID_AA64ISAR1_EL1 definitions */
 #define ID_AA64ISAR1_EL1	S3_0_C0_C6_1
 #define ID_AA64ISAR1_GPI_SHIFT	U(28)