nvme-tcp: fix an endianess miss-annotation

nvme_tcp_end_request just takes the status value and the converts
it to little endian as well as shifting for the phase bit.

Fixes: 43ce38a6d823 ("nvme-tcp: support C2HData with SUCCESS flag")
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>