ARM: dts: msm: Add a minimum target-quotient difference of 0 for 8939

There is a possibility that after quotient-adjustment the NOM
target-quotient might be <= (TURBO target-quotient - 50).
Specify the minimum quotient difference in order to keep
CPR from being disabled.

CRs-Fixed: 762377
Change-Id: I1a64df45bddbba76698516124355423d88ef9d59
Signed-off-by: Anirudh Ghayal <aghayal@codeaurora.org>