i965/fs: Implement lowering of logical texturing opcodes on Gen5-6.
i965/fs: Implement lowering of logical texturing opcodes on Gen5-6.

This should be largely equivalent to emit_texture_gen5() except for
slight codestyle changes and the use i965 opcodes instead of the
ir_texture_opcode enum, see "i965/fs: Implement lowering of logical
texturing opcodes on Gen7+." for the mapping between them.

Reviewed-by: Jason Ekstrand <b186559eaedf698788888c8a2559b4efb4db10d6@intel.com>
Reviewed-by: Kenneth Graunke <bd2562f754ec92342f93f61c25d731e290a2ffa8@whitecape.org>

metora/MesaGLSLCompiler,metora/MesaGLSLCompiler,metora/MesaGLSLCompiler