i965: Convert brw_disasm.c to the new brw_inst API.

i965: Convert brw_disasm.c to the new brw_inst API.

v2: (by Kenneth Graunke)
 - Fix disassembly of Gen4-5 SEND messages to print base MRF correctly.
 - Only print URB opcode on Gen5+, to match previous output (besides,
   there is only one opcode AFAICT.)
 - Only print the low 3 bits of msg_control, to match previous output.
   (We probably should decode all the fields, but hadn't previously due
   to the brw_instruction structure definition splitting out bits 4/5
   for last_render_target and slot_group_select.)
 - Fix 3-source MRF/GRF file decoding on Sandybridge.
 - Fix compression code to use qtr_control rather than cmpt_control
   (which is compaction, not compression).

Signed-off-by: Matt Turner <mattst88@gmail.com>
Signed-off-by: Kenneth Graunke <kenneth@whitecape.org> [v2]
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>