IB/isert: Avoid frwr notation, user fastreg

Use fast registration lingo. fast registration will
also incorporate signature/DIF registration.

Signed-off-by: Sagi Grimberg <sagig@mellanox.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

diff --cc drivers/infiniband/ulp/isert/ib_isert.c
Simple merge

diff --cc drivers/infiniband/ulp/isert/ib_isert.h
Simple merge