msm: kgsl: Use the correct register for the TWO_PASS_WFI quirk

The TWOPASSUSEWFI bit is in the PC_DBG_ECO_CNTL register like the
comment says, not the SP_DBG_ECO_CNTL register that was accidently
being written.

Change-Id: Ic0dedbadd0f5a87af6ff94a4f5c6c1fecabf1daf
Signed-off-by: Jordan Crouse <jcrouse@codeaurora.org>