i965/vec4: Clamp indirect tes input array reads with 0x0fffffff

Page 190 of "Volume 7: 3D Media GPGPU Engine (Haswell)" says the valid
range of the offset is [0, 0FFFFFFFh].

Signed-off-by: Ian Romanick <ian.d.romanick@intel.com>
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
Cc: mesa-stable@lists.freedesktop.org
(cherry picked from commit 82530ce1)