[CPUFREQ] s5pv210: make needlessly global symbols static

The following symbols are needlessly defined global:
  s5pv210_verify_speed
  s5pv210_getspeed

Make them static.

Signed-off-by: Axel Lin <axel.lin@gmail.com>
Acked-by: Kukjin Kim <kgene.kim@samsung.com>
Signed-off-by: Dave Jones <davej@redhat.com>