msm: kgsl: Remove drawctxt_active from setstate default

drawctxt_active is cleared after the old context is removed
during context switch.  Unfortunately, the context restore calls
adreno_use_default_setstate() which always returns true if
drawctxt_active is NULL, effectively always forcing us down the
software path.

Remove the check - adreno_use_default_setstate() already checks to see
if the GPU is idle and that is a more reliable verification that the
software path is worth going down.

Change-Id: Ic0dedbad57d7783bc23dd925a277a63cd2d78a7e
Signed-off-by: Jordan Crouse <jcrouse@codeaurora.org>