Simplify linux_exec_setregs

[trasz]

Summary

Simplify linux_exec_setregs() by not duplicating exec_setregs().
No functional changes intended.

[mhorne]

Seems that this could be done in linux32_sysvec.c as well using ia32_setregs().

[trasz]

I'm not sure if the call to setup_lcall_gate() is safe for Linux binaries?

[kib]

I do not like it. It makes changes to exec_setregs() to suddenly affect linuxolator.

In other review, you stop using native set_retval() in linux variant. So why move in reverse direction there ?

If so inclined extract the absolutely common code into some neutrally-named function and call it both from linux_exec_setregs() and exec_setregs().

[trasz]

Yeah, you're right, this would be step in the wrong direction.