sim: Use the new returnInto method in cloneFunc.

This gets rid of the final use of setSyscallReturn.

Change-Id: I1108df0c5c72b5dec60128dced48ac0fd0356d24
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/23504
Tested-by: kokoro <noreply+kokoro@google.com>
Reviewed-by: Bobby R. Bruce <bbruce@ucdavis.edu>
Maintainer: Gabe Black <gabeblack@google.com>

src/sim/syscall_emul.hh

@@ -1529,7 +1529,7 @@ cloneFunc(SyscallDesc *desc, int callnum, ThreadContext *tc,
 
     OS::archClone(flags, p, cp, tc, ctc, newStack, tlsPtr);
 
-    cp->setSyscallReturn(ctc, 0);
+    desc->returnInto(ctc, 0);
 
 #if THE_ISA == SPARC_ISA
     tc->setIntReg(TheISA::SyscallPseudoReturnReg, 0);