intel/eu: Split brw_inst ex_desc accessors for SEND(C) vs. SENDS(C).

The brw_inst opcode accessors are going away in one of the following
commits.  We could potentially replace them with the new helpers that
do opcode remapping, but that would lead to a circular dependency
between brw_inst.h and brw_eu.h.  This way we also avoid ordering
issues that can cause the semantics of the ex_desc accessors to change
depending on whether the ex_desc field is set after or before the
opcode instruction field.

Reviewed-by: Caio Marcelo de Oliveira Filho <caio.oliveira@intel.com>
Reviewed-by: Jordan Justen <jordan.l.justen@intel.com>
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>

src/intel/compiler/brw_eu_validate.c

@@ -348,7 +348,7 @@ send_restrictions(const struct gen_device_info *devinfo,
 
          unsigned ex_mlen = 1;
          if (!brw_inst_send_sel_reg32_ex_desc(devinfo, inst)) {
-            const uint32_t ex_desc = brw_inst_send_ex_desc(devinfo, inst);
+            const uint32_t ex_desc = brw_inst_sends_ex_desc(devinfo, inst);
             ex_mlen = brw_message_ex_desc_ex_mlen(devinfo, ex_desc);
          }
          const unsigned src0_reg_nr = brw_inst_src0_da_reg_nr(devinfo, inst);