st/mesa: fix GS varyings for PIPE_CAP_TGSI_TEXCOORD
nv50: add more RGB10A2 formats
mesa/st: expose ARB_texture_rgb10_a2ui if R10G10B10A2_UINT is supported v2

Reviewed-by: Marek Olšák <marek.olsak@amd.com>
nv50, nvc0: update reported glsl version to 330

Signed-off-by: Ilia Mirkin <imirkin@alum.mit.edu>