i965/fs: Perform CSE on sends-from-GRF rather than textures.

Should potentially allow a few more cases, while avoiding doing CSE on
texture operations on Gen <= 6 with the MRF.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=80211
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
Tested-by: lu hua <huax.lu@intel.com>

src/mesa/drivers/dri/i965/brw_fs_cse.cpp

@@ -103,7 +103,7 @@ is_expression(const fs_inst *const inst)
    case SHADER_OPCODE_LOAD_PAYLOAD:
       return !is_copy_payload(inst);
    default:
-      return inst->is_tex();
+      return inst->is_send_from_grf();
    }
 }