[PATCH v2 1/2] nvmet-tcp: support specifying the congestion-control

[Mingbao Sun]

The patch v1 for target side also inserted some calls to
networking APIs in the generic part (configfs.c) for validating
the congestion-control specified by the user.

Per the comments from Christoph Hellwig on 
‘[PATCH 2/2] nvme-tcp: support specifying the congestion-control’
(the patch for the host side), here delete these calls.

Since the tcp_congestion specified by the user could also get
checked later within sock_common_setsockopt in nvmet_tcp_add_port.
So this deletion brings little downside.