msm: kgsl: Turn on SP/TP enable bit statically

Setting the enable bit in a4xx_start forces it to always stay on.
Set the SP/TP enable bit statically so that sysfs routines can
set/unset the bit.

Change-Id: I60828cfde69c2ceb6a5f21466f5f7a36c84a572a
Signed-off-by: Suman Tatiraju <sumant@codeaurora.org>