tests/srp: fix module loading issue during srp tests

The ib_isert/ib_srpt modules will be automatically loaded after the first
 time rdma_rxe/siw setup, which will lead srp tests fail.

$ modprobe rdma_rxe
$ echo eno1 >/sys/module/rdma_rxe/parameters/add
$ lsmod | grep -E "ib_srpt|iscsi_target_mod|ib_isert"
ib_srpt               167936  0
ib_isert              139264  0
iscsi_target_mod      843776  1 ib_isert
target_core_mod      1069056  3 iscsi_target_mod,ib_srpt,ib_isert
rdma_cm               315392  5 rpcrdma,ib_srpt,ib_iser,ib_isert,rdma_ucm
ib_cm                 344064  2 rdma_cm,ib_srpt
ib_core              1101824  10 rdma_cm,rdma_rxe,rpcrdma,ib_srpt,iw_cm,ib_iser,ib_isert,rdma_ucm,ib_uverbs,ib_cm

$ ./check srp/001
srp/001 (Create and remove LUNs)                             [failed]
    runtime    ...  3.675s
    --- tests/srp/001.out	2021-10-13 01:18:50.846740093 -0400
    +++ /root/blktests/results/nodev/srp/001.out.bad	2021-10-14 03:24:18.593852208 -0400
    @@ -1,3 +1 @@
    -Configured SRP target driver
    -count_luns(): 3 <> 3
    -Passed
    +insmod: ERROR: could not insert module /lib/modules/5.15.0-rc5.fix+/kernel/drivers/infiniband/ulp/srpt/ib_srpt.ko: File exists
modprobe: FATAL: Module iscsi_target_mod is in use.

Reviewed-by: Bart Van Assche <[email protected]>
Signed-off-by: Yi Zhang <[email protected]>

Author: yizhanglinux

tests/srp/rc

@@ -494,7 +494,8 @@ start_lio_srpt() {
 	if modinfo ib_srpt | grep -q '^parm:[[:blank:]]*rdma_cm_port:'; then
 		opts+=("rdma_cm_port=${srp_rdma_cm_port}")
 	fi
-	insmod "/lib/modules/$(uname -r)/kernel/drivers/infiniband/ulp/srpt/ib_srpt."* "${opts[@]}" || return $?
+	unload_module ib_srpt
+	modprobe ib_srpt "${opts[@]}" || return $?
 	i=0
 	for r in "${vdev_path[@]}"; do
 		if [ -b "$(readlink -f "$r")" ]; then
@@ -551,7 +552,7 @@ stop_lio_srpt() {
 	rmdir /sys/kernel/config/target/*/* >&/dev/null
 	rmdir /sys/kernel/config/target/* >&/dev/null
 
-	for m in ib_srpt iscsi_target_mod target_core_pscsi target_core_iblock \
+	for m in ib_srpt ib_isert iscsi_target_mod target_core_pscsi target_core_iblock \
 			 target_core_file target_core_stgt target_core_user \
 			 target_core_mod
 	do