gallium: bump shader input and output limits

We hit an assert when we run Piglit in the guest. Fix spec@arb_tessellation_shader@execution@variable-indexing@tes-both-input-array-vec3-index-rd

Same commit as 7ffc1fb9282 from Mesa.

Signed-off-by: Elie Tournier <elie.tournier@collabora.com>