linux(4): make getcwd(2) return ERANGE instead of ENOMEM

For native FreeBSD binaries, the return value from __getcwd(2)
doesn't really matter, as the libc wrapper takes over and returns
the proper errno.

PR: kern/254120
Reported By: Alex S <iwtcex@gmail.com>
Reviewed By: kib
Sponsored By: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D29217