MIPS: Fix "bad FP FLOAD" assertion.

Reported by Sergey Kaplun. #1043

src/lj_asm_mips.h

@@ -1337,8 +1337,8 @@ static void asm_fload(ASMState *as, IRIns *ir)
       }
     }
     ofs = field_ofs[ir->op2];
+    lj_assertA(!irt_isfp(ir->t), "bad FP FLOAD");
   }
-  lj_assertA(!irt_isfp(ir->t), "bad FP FLOAD");
   emit_tsi(as, mi, dest, idx, ofs);
 }