msm: kgsl: Do not disable interrupts when removing GMU

We already disable interrupts during gmu_stop(), which
is called in gmu_remove(). Subsequently, don't disable
interrupts again.

Change-Id: I6d4f9bcd73243909e1a41fc8dd72f7668fcb7343
Signed-off-by: Kyle Piefer <kpiefer@codeaurora.org>