edac: i5000: improve handling of pci_enable_device() return value

-EIO is not the only error code that pci_enable_device() may return, also
the set of errors can be enhanced in future.  We should compare return
code with zero, not with concrete error value.

Signed-off-by: Kulikov Vasiliy <segooon@gmail.com>
Acked-by: Mauro Carvalho Chehab <mchehab@redhat.com>
Cc: Jeff Roberson <jroberson@jroberson.net>
Cc: Doug Thompson <dougthompson@xmission.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>