tgsi: collect texture sampler target info in tgsi_scan_shader()

tgsi: collect texture sampler target info in tgsi_scan_shader()

Texture sample instructions specify a sampler unit and texture target
such as "1D", "2D", "CUBE", etc.  Sampler view declarations also specify
the sampler unit and texture target.

This patch checks that the texture instructions agree with the declarations
and collects the texture target type for each sampler unit.

v2: only compare instruction's texture target to the sampler view declaration
target if the instruction is a TEX instruction, not a SAMPLE instruction.

Reviewed-by: José Fonseca <jfonseca@vmware.com>
Reviewed-by: Roland Scheidegger <sroland@vmware.com>