[CPUFREQ] s3c64xx: Fix mis-cherry pick of VDDINT

We don't have any of the other code for VDDINT, including the variable
declaration, so don't try to get it as we can't build.

Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Dave Jones <davej@redhat.com>