EmbeddedPkg: 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
EmbeddedPkg.

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>
Reviewed-by: Abner Chang <abner.chang@amd.com>

EmbeddedPkg/RealTimeClockRuntimeDxe/RealTimeClock.c

@@ -219,7 +219,7 @@ InitializeRealTimeClock (
     DEBUG ((
       DEBUG_WARN,
       "%a: using default timezone/daylight settings\n",
-      __FUNCTION__
+      __func__
       ));
 
     mTimeSettings.TimeZone = EFI_UNSPECIFIED_TIMEZONE;