Makefile: Add 'make mrproper' for removing all bin/elf/etc output files

Change-Id: I01e4b3f0224977fd38ed126f37f33ac9324f5abc
diff --git a/sysmoOCTSIM/gcc/Makefile b/sysmoOCTSIM/gcc/Makefile
index d98277a..c587fdd 100644
--- a/sysmoOCTSIM/gcc/Makefile
+++ b/sysmoOCTSIM/gcc/Makefile
@@ -223,3 +223,6 @@
 	rm -f $(OUTPUT_FILE_NAME).a $(OUTPUT_FILE_NAME).hex $(OUTPUT_FILE_NAME).bin \
         $(OUTPUT_FILE_NAME).lss $(OUTPUT_FILE_NAME).eep $(OUTPUT_FILE_NAME).map \
         $(OUTPUT_FILE_NAME).srec
+
+mrproper: clean
+	rm -f *.o *.d *.a *.elf *.bin *.ihex *.eep *.lss *.map *.srec