pid: fix mips irix emulation pid usage

pid: fix mips irix emulation pid usage

[m.kozlowski@tuxland.pl: fix unbalanced parenthesis in irix_BSDsetpgrp()]
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Cc: Pavel Emelyanov <xemul@openvz.org>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: Mariusz Kozlowski <m.kozlowski@tuxland.pl>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>