octeontx2-pf: Delete duplicate work queue

Since commit e99b7c84 ("octeontx2-pf: Fix ndo_set_rx_mode"), workqueue
'otx2_wq' has been added to the kernel. Delete the duplicate work queue that
caused follow panic in file otx2_flows.c.

    Unable to handle kernel paging request at virtual address dead000000000122
    Mem abort info:
      ESR = 0x96000044
      EC = 0x25: DABT (current EL), IL = 32 bits
      SET = 0, FnV = 0
      EA = 0, S1PTW = 0
    Data abort info:
      ISV = 0, ISS = 0x00000044
      CM = 0, WnR = 1
    [dead000000000122] address between user and kernel address ranges
    Internal error: Oops: 96000044 [#1] PREEMPT SMP
    Modules linked in: 8021q sch_fq_codel openvswitch nsh nf_conncount nf_nat
		       nf_conntrack nf_defrag_ipv6 nf_defrag_ipv4
    CPU: 15 PID: 1 Comm: systemd-shutdow Not tainted 5.9.0-rc6-yoctodev-standard #1
    Hardware name: Marvell OcteonTX CN96XX board (DT)
    pstate: 60400009 (nZCv daif +PAN -UAO BTYPE=--)
    pc : destroy_workqueue+0x18c/0x250
    lr : destroy_workqueue+0x178/0x250
    sp : ffff800011cafbf0
    x29: ffff800011cafbf0 x28: ffff000bc0900000
    x27: 0000000000000000 x26: ffff000bc5eef128
    x25: ffff800010dc4678 x24: 0000000000000008
    x23: ffff000bc9a04c20 x22: ffff80001135c1d0
    x21: ffff000bc9a04c00 x20: ffff000bc9a04b90
    x19: ffff000bc8d11a58 x18: 000000000000000e
    x17: 000002f62aafd018 x16: 000bd9d4a91fb000
    x15: 0000000000000019 x14: ffff800010bc1588
    x13: 0000000000000001 x12: 000000000000023b
    x11: 0000000094f4efa8 x10: 000000000000034d
    x9 : ffff80001004fca8 x8 : 0000000000000001
    x7 : 00000000810000fb x6 : 0000000000000001
    x5 : 0000000000000001 x4 : ffff000bc0900000
    x3 : dead000000000122 x2 : ffff000bc9b6ce10
    x1 : dead000000000122 x0 : ffff80001135c208
    Call trace:
     destroy_workqueue+0x18c/0x250
     otx2_mcam_flow_del+0x30/0x40
     otx2_remove+0x9c/0x15c
     pci_device_shutdown+0x40/0x50
     device_shutdown+0x160/0x334
     __do_sys_reboot+0x1d8/0x260
     __arm64_sys_reboot+0x30/0x40
     do_el0_svc+0x8c/0x1e0
     el0_sync_handler+0x90/0x194
     el0_sync+0x158/0x180
    Code: f9000441 d2802443 9100e2c0 f2fbd5a3 (f9000022)
    ---[ end trace c982aa80d60b95ce ]---
    Kernel panic - not syncing: Attempted to kill init! exitcode=0x0000000b
    Kernel Offset: disabled
    CPU features: 0x6040002,2a808a38
    Memory Limit: none
    ---[ end Kernel panic - not syncing: Attempted to kill init! exitcode=0x0000000b ]---

Signed-off-by: Ruiqiang Hao <Ruiqiang.Hao@windriver.com>