sh: smp: Protect setup_profiling_timer() by CONFIG_PROFILING

arch/sh/kernel/smp.c:326:5: warning: no previous prototype for 'setup_profiling_timer' [-Wmissing-prototypes]

The function is unconditionally defined in smp.c, but conditionally
declared in <linux/profile.h>.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>
Link: https://lore.kernel.org/r/effa5eecbd2389c6661974e91bb834db210989ea.1715606232.git.geert+renesas@glider.be


Signed-off-by: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>