SPARC: add prlimit and prlimit64 in <bits/resource.h> (BZ #16943)

prlimit and prlimit64 have been added in the main <bits/resource.h>, but
not in the SPARC specific version. Fix that.

Note: this is Debian bug#703559, reported by Emilio Pozuelo Monfort
<pochu@debian.org>