msm: kgsl: fix 2d kgsl_pwrctrl_irq() call

The call to turn on the 2d irq from z180_start() would have
no effect because it was using the wrong flag. The offending flags,
which should only be used from within kgsl_pwrctrl.c for setting bits
in struct kgsl_pwrctrl.power_flags are also moved to the .c file
to avoid problems like this in the future.

Change-Id: Ied48c5f3b4860d55b2c0b7019ba50ed22d7f6bc1
Signed-off-by: Jeremy Gebben <jgebben@codeaurora.org>