Fix the following sparse warnings:

arch/arm/mach-imx/cpu-imx5.c:65:12: warning: symbol 'mx51_neon_fixup' was not declared. Should it be static?
arch/arm/mach-imx/cpu-imx5.c:99:5: warning: symbol 'mx53_revision' was not declared. Should it be static?
Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>
Signed-off-by: Shawn Guo <shawn.guo@linaro.org>