ArmPkg/ArmLib: Add ArmHasEte () helper function

Create a helper function to query whether ID_AA64MFR1_EL1 indicates
presence of the Embedded Trace Extension (ETE). This feature is only
visible in AARCH64 state.

Cc: Ard Biesheuvel <ardb+tianocore@kernel.org>
Cc: Leif Lindholm <quic_llindhol@quicinc.com>
Cc: Pierre Gondois <pierre.gondois@arm.com>
Signed-off-by: Sami Mujawar <sami.mujawar@arm.com>
Reviewed-by: Leif Lindholm <quic_llindhol@quicinc.com>
Reviewed-by: Pierre Gondois <pierre.gondois@arm.com>

ArmPkg/Library/ArmLib/AArch64/AArch64Lib.c

@@ -134,3 +134,19 @@ ArmHasTrbe (
 {
   return ((ArmReadIdAA64Dfr0 () & AARCH64_DFR0_TRBE) != 0);
 }
+
+/**
+  Checks whether the CPU implements the Embedded Trace Extension.
+
+  @retval TRUE  FEAT_ETE is implemented.
+  @retval FALSE FEAT_ETE is not mplemented.
+**/
+BOOLEAN
+EFIAPI
+ArmHasEte (
+  VOID
+  )
+{
+  // The ID_AA64DFR0_EL1.TraceVer field identifies the presence of FEAT_ETE.
+  return ((ArmReadIdAA64Dfr0 () & AARCH64_DFR0_TRACEVER) != 0);
+}