[SCSI] mpt fusion: don't oops if NumPhys==0

Don't oops if NumPhys==0, instead return -ENODEV.
This patch fixes http://bugzilla.kernel.org/show_bug.cgi?id=9909

Signed-off-by: Krzysztof Piotr Oledzki <ole@ans.pl>
Acked-by: Eric Moore <Eric.Moore@lsi.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>