regulator: cpr-regulator: reduce the minimum allowed quotient difference

Reduce the minimum CPR target quotient difference allowed between
the highest and second highest fuse corners from 100 to 50.  This
ensures that CPR stays enabled for VDD_APC1 on MSM8994v2.  The
CPR ring oscillators used for VDD_APC1 on MSM8994v2 output low
values.  Therefore, the difference between the Turbo and Nominal
target quotient fuse values may legitimately be less than 100.

Change-Id: Ia662dd05f3af9148a63298900970cdb0c0824c50
Signed-off-by: David Collins <collinsd@codeaurora.org>