i965: Add UD null register helpers.

Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>

src/mesa/drivers/dri/i965/brw_fs.h

@@ -109,6 +109,7 @@ public:
 static const fs_reg reg_undef;
 static const fs_reg reg_null_f(ARF, BRW_ARF_NULL, BRW_REGISTER_TYPE_F);
 static const fs_reg reg_null_d(ARF, BRW_ARF_NULL, BRW_REGISTER_TYPE_D);
+static const fs_reg reg_null_ud(ARF, BRW_ARF_NULL, BRW_REGISTER_TYPE_UD);
 
 class ip_record : public exec_node {
 public:

src/mesa/drivers/dri/i965/brw_vec4.h

@@ -245,6 +245,11 @@ public:
       return dst_reg(retype(brw_null_reg(), BRW_REGISTER_TYPE_D));
    }
 
+   dst_reg dst_null_ud()
+   {
+      return dst_reg(retype(brw_null_reg(), BRW_REGISTER_TYPE_UD));
+   }
+
    struct gl_program *prog;
    struct brw_vec4_compile *c;
    const struct brw_vec4_prog_key *key;