ARM: remove disable_fiq and arch_ret_to_user macros

Now that most platforms don't need disable_fiq and arch_ret_to_user
macros, we can remove the empty macros or empty entry-macro.S files.

Signed-off-by: Rob Herring <rob.herring@calxeda.com>
Acked-by: Jamie Iles <jamie@jamieiles.com>
Acked-by: Nicolas Pitre <nico@linaro.org>
Acked-by: Tony Lindgren <tony@atomide.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Acked-by: Ryan Mallon <rmallon@gmail.com>
Acked-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Acked-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Acked-by: Shawn Guo <shawn.guo@linaro.org>