nvmet: set right status on error in id-ns handler

The function nvmet_execute_identify_ns() doesn't set the status if call
to nvmet_find_namespace() fails. In that case we set the status of the
request to the value return by the nvmet_copy_sgl().

Set the status to NVME_SC_INVALID_NS and adjust the code such that
request will have the right status on nvmet_find_namespace() failure.

Without this patch :-
NVME Identify Namespace 3:
nsze    : 0
ncap    : 0
nuse    : 0
nsfeat  : 0
nlbaf   : 0
flbas   : 0
mc      : 0
dpc     : 0
dps     : 0
nmic    : 0
rescap  : 0
fpi     : 0
dlfeat  : 0
nawun   : 0
nawupf  : 0
nacwu   : 0
nabsn   : 0
nabo    : 0
nabspf  : 0
noiob   : 0
nvmcap  : 0
mssrl   : 0
mcl     : 0
msrc    : 0
nsattr	: 0
nvmsetid: 0
anagrpid: 0
endgid  : 0
nguid   : 00000000000000000000000000000000
eui64   : 0000000000000000
lbaf  0 : ms:0   lbads:0  rp:0 (in use)

With this patch-series :-
feb3b88b501e (HEAD -> nvme-5.11) nvmet: remove extra variable in identify ns
6302aa67210a nvmet: remove extra variable in id-desclist
ed57951da453 nvmet: remove extra variable in smart log nsid
be384b8c24dc nvmet: set right status on error in id-ns handler

NVMe status: INVALID_NS: The namespace or the format of that namespace is invalid(0xb)

Signed-off-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Christoph Hellwig <hch@lst.de>