ArmVirtPkg: Update code to be more C11 compliant by using __func__

__FUNCTION__ is a pre-standard extension that gcc and Visual C++ among
others support, while __func__ was standardized in C99.

Since it's more standard, replace __FUNCTION__ with __func__ throughout
ArmVirtPkg.

Signed-off-by: Rebecca Cran <rebecca@bsdio.com>
Reviewed-by: Michael D Kinney <michael.d.kinney@intel.com>
Reviewed-by: Ard Biesheuvel <ardb@kernel.org>

ArmVirtPkg/CloudHvAcpiPlatformDxe/CloudHvAcpi.c

@@ -106,7 +106,7 @@ InstallCloudHvAcpiTables (
   } // while
 
   if (DsdtPtr == NULL) {
-    DEBUG ((DEBUG_ERROR, "%a: no DSDT found\n", __FUNCTION__));
+    DEBUG ((DEBUG_ERROR, "%a: no DSDT found\n", __func__));
     return EFI_NOT_FOUND;
   }
 
@@ -151,7 +151,7 @@ CloudHvAcpiPlatformEntryPoint (
     DEBUG ((
       DEBUG_ERROR,
       "%a: Fail to install Acpi table: %r\n",
-      __FUNCTION__,
+      __func__,
       Status
       ));
     CpuDeadLoop ();