Partially revert #1326

Apparently GCC still wants the UNUSED.

Not sure why CI didn't catch this initially.

riscv/v_ext_macros.h

@@ -341,12 +341,12 @@ static inline bool is_aligned(const unsigned val, const unsigned pos)
   type_usew_t<x>::type vs2 = P.VU.elt<type_usew_t<x>::type>(rs2_num, i);
 
 #define VV_PARAMS(x) \
-  type_sew_t<x>::type &vd = P.VU.elt<type_sew_t<x>::type>(rd_num, i, true); \
+  type_sew_t<x>::type UNUSED &vd = P.VU.elt<type_sew_t<x>::type>(rd_num, i, true); \
   type_sew_t<x>::type vs1 = P.VU.elt<type_sew_t<x>::type>(rs1_num, i); \
   type_sew_t<x>::type UNUSED vs2 = P.VU.elt<type_sew_t<x>::type>(rs2_num, i);
 
 #define VX_PARAMS(x) \
-  type_sew_t<x>::type &vd = P.VU.elt<type_sew_t<x>::type>(rd_num, i, true); \
+  type_sew_t<x>::type UNUSED &vd = P.VU.elt<type_sew_t<x>::type>(rd_num, i, true); \
   type_sew_t<x>::type rs1 = (type_sew_t<x>::type)RS1; \
   type_sew_t<x>::type UNUSED vs2 = P.VU.elt<type_sew_t<x>::type>(rs2_num, i);