msm:kgsl: Enable GPU peak current threshold setting

Sets correct enabling bitmask to request GMU to take
new peak current limit setting.

CRs-Fixed: 2120475
Signed-off-by: Oleg Perelet <operelet@codeaurora.org>
Change-Id: I8199423cf97dc549f567974a03e23901ed1563f5
Signed-off-by: George Shen <sqiao@codeaurora.org>