svga: remove SVGA_RELOC_READ flag in SVGA3D_BindGBSurface()
This fixes a rendering issue where UBO updates aren't always picked up by drawing calls. This issue effected the Webots robotics simulator. VMware bug 2175527. Testing Done: Webots replay, piglit, misc Linux games Reviewed-by:Thomas Hellstrom <thellstrom@vmware.com> (cherry picked from commit d4381cf5)