[PATCH] uml: activate_fd: return ENOMEM only when appropriate

Avoid returning ENOMEM in case of a duplicate IRQ - ENOMEM was saved into err
earlier.

Signed-off-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Acked-by: Jeff Dike <jdike@addtoit.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>