mali: Fix mali regulator clk handling on suspned/resume

Finally narrowed the graphics related suspend/resume hard hang
down to the hikey mali code mishandling the regulator clocks.

Xinliang suggested the following fix, which corrects
the handling of the mali_pclk_g3d.

With this fix, suspend and resume work fine on the board.

Change-Id: Ibd89359528356a88ee4c1aa6381d0516a7b59894
Signed-off-by: John Stultz <john.stultz@linaro.org>