profiling: Remove create_prof_cpu_mask().

create_prof_cpu_mask() is no longer used after commit 1f44a225

 ("s390:
convert interrupt handling to use generic hardirq").

Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>