nvme-rdma: unquiesce admin_q before destroy it

In the Linux kernel, the following vulnerability has been resolved:

nvme-rdma: unquiesce admin_q before destroy it

Kernel will hang on destroy admin_q while we create ctrl failed, such
as following calltrace:

PID: 23644 TASK: ff2d52b40f439fc0 CPU: 2 COMMAND: "nvme"
#0 [ff61d23de260fb78] __schedule at ffffffff8323bc15
#1 [ff61d23de260fc08] schedule at ffffffff8323c014
#2 [ff61d23de260fc28] blk_mq_freeze_queue_wait at ffffffff82a3dba1
#3 [ff61d23de260fc78] blk_freeze_queue at ffffffff82a4113a
#4 [ff61d23de260fc90] blk_cleanup_queue at ffffffff82a33006
#5 [ff61d23de260fcb0] nvme_rdma_destroy_admin_queue at ffffffffc12686ce
#6 [ff61d23de260fcc8] nvme_rdma_setup_ctrl at ffffffffc1268ced
#7 [ff61d23de260fd28] nvme_rdma_create_ctrl at ffffffffc126919b
#8 [ff61d23de260fd68] nvmf_dev_write at ffffffffc024f362
#9 [ff61d23de260fe38] vfs_write at ffffffff827d5f25
RIP: 00007fda7891d574 RSP: 00007ffe2ef06958 RFLAGS: 00000202
RAX: ffffffffffffffda RBX: 000055e8122a4d90 RCX: 00007fda7891d574
RDX: 000000000000012b RSI: 000055e8122a4d90 RDI: 0000000000000004
RBP: 00007ffe2ef079c0 R8: 000000000000012b R9: 000055e8122a4d90
R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000004
R13: 000055e8122923c0 R14: 000000000000012b R15: 00007fda78a54500
ORIG_RAX: 0000000000000001 CS: 0033 SS: 002b

This due to we have quiesced admi_q before cancel requests, but forgot
to unquiesce before destroy it, as a result we fail to drain the
pending requests, and hang on blk_mq_freeze_queue_wait() forever. Here
try to reuse nvme_rdma_teardown_admin_queue() to fix this issue and
simplify the code.