staging: lustre: Fix unneeded byte-ordering cast

Fix sparse warning:

  CHECK   drivers/staging//lustre/lnet/lnet/acceptor.c
drivers/staging//lustre/lnet/lnet/acceptor.c:243:30: warning: cast to
restricted __le32

LNET_PROTO_TCP_MAGIC, as a define, is already CPU byte-ordered when
compared to 'magic', so no need for a cast.

Signed-off-by: Justin Skists <j.skists@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>