cmd/compile: remove the resultInArg0 register checks on linux/loong64

The automatic resultInArg0 register check has been implemented by CL 296010.

Change-Id: Id0e085ded9aa097bd02593c359a750d938a3aaa6
Reviewed-on: https://go-review.googlesource.com/c/go/+/416034
Reviewed-by: Keith Randall <[email protected]>
TryBot-Result: Gopher Robot <[email protected]>
Reviewed-by: Keith Randall <[email protected]>
Reviewed-by: Wayne Zuo <[email protected]>
Run-TryBot: Wayne Zuo <[email protected]>
Reviewed-by: Bryan Mills <[email protected]>

Author: abner-chenc

src/cmd/compile/internal/loong64/ssa.go

@@ -101,9 +101,6 @@ func ssaGenValue(s *ssagen.State, v *ssa.Value) {
 		p.To.Type = obj.TYPE_REG
 		p.To.Reg = y
 	case ssa.OpLOONG64MOVVnop:
-		if v.Reg() != v.Args[0].Reg() {
-			v.Fatalf("input[0] and output not in same register %s", v.LongString())
-		}
 		// nothing to do
 	case ssa.OpLoadReg:
 		if v.Type.IsFlags() {