msm: kgsl: Fix voltage dependency table logic

ARC values might not always be unique and increasing.
If a voltage corner is deactivated, cmddb could reuse
values, causing strings of repeats in the list.
Fix potential incorrect counting of the values from
cmddb by stopping the count on hitting 0 padding
instead of on hitting a duplicate or lower value.

Also, look for a primary rail voltage greater than
or equal to a VLVL value instead of equal to, for
the same reason. Then use this value to find a
secondary rail value.

Change-Id: If5996b5d4a4319248f95be9138cd380db519a8a6
Signed-off-by: Kyle Piefer <kpiefer@codeaurora.org>