Fix _glamor_set_spans() bug (re-used 'n' variable)

n was used as a function parameter.  But inside the for (i=1..n) loop,
n got reassigned as REGION_NUM_RECTS() and then decremented to zero by
the while loop.  This caused the for loop to only iterate once instead
of 'n' times.

This patch renames the n parameter to numPoints.

Found by code inspection.  Untested.

Reviewed-by: Zhigang Gong <zhigang.gong@linux.intel.com>
Remove redundant dispatch->glEnable(GL_TEXTURE_2D)

The same call was already made a few lines earlier.

Reviewed-by: Zhigang Gong <zhigang.gong@linux.intel.com>
Remove useless return statement

Reviewed-by: Zhigang Gong <zhigang.gong@linux.intel.com>
Fixed an incorrect printf format.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=69573

Signed-off-by: Zhigang Gong <zhigang.gong@linux.intel.com>