ARM: shmobile: Add includes providing forward declarations

make C=1:

    arch/arm/mach-shmobile/timer.c:38:13: warning: symbol 'shmobile_init_delay' was not declared. Should it be static?
    arch/arm/mach-shmobile/suspend.c:37:29: warning: symbol 'shmobile_suspend_ops' was not declared. Should it be static?
    arch/arm/mach-shmobile/suspend.c:44:12: warning: symbol 'shmobile_suspend_init' was not declared. Should it be static?
    arch/arm/mach-shmobile/cpufreq.c:13:12: warning: symbol 'shmobile_cpufreq_init' was not declared. Should it be static?

Include "common.h" to fix these.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>