tools/firmware: Add missing newline at end of file

"git diff" says:

    \ No newline at end of file

after modifying the file.
Signed-off-by: NGeert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

tools/firmware/Makefile

@@ -10,4 +10,4 @@ all: ihex2fw
 clean:
 	$(RM) ihex2fw
 
-.PHONY: all clean
\ No newline at end of file
+.PHONY: all clean