ArmPkg/ArmV7Lib: add function to test for presence of MP extensions

Some MMU manipulation is dependent on the presence of the multiprocessing
extensions. So add a function that returns this information.

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Reviewed-by: Leif Lindholm <leif.lindholm@linaro.org>

git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@18895 6f19259b-4bc3-4df7-8a09-765794883524

ArmPkg/Library/ArmLib/ArmV7/ArmV7Lib.h

@@ -28,5 +28,11 @@ ArmReadIdMmfr0 (
   VOID
   );
 
+BOOLEAN
+EFIAPI
+ArmHasMpExtensions (
+  VOID
+  );
+
 #endif // __ARM_V7_LIB_H__