[AVR] Match 16-bit static data load instructions to LPMWRdZ

(avr-rust/rust-legacy-fork#47)

Author: gergoerdi

lib/Target/AVR/AVRInstrInfo.td

@@ -1203,7 +1203,7 @@ isReMaterializable = 1 in
   def LDWRdPtr : Pseudo<(outs DREGS:$reg),
                         (ins PTRDISPREGS:$ptrreg),
                         "ldw\t$reg, $ptrreg",
-                        [(set i16:$reg, (load i16:$ptrreg))]>,
+                        []>,
                  Requires<[HasSRAM]>;
 }
 
@@ -1465,7 +1465,7 @@ hasSideEffects = 0 in
   def LPMWRdZ : Pseudo<(outs DREGS:$dst),
                        (ins ZREGS:$z),
                        "lpmw\t$dst, $z",
-                       []>,
+                       [(set DREGS:$dst, (load i16:$z))]>,
                 Requires<[HasLPMX]>;
 
   // Load program memory, while postincrementing the Z register.