usb: dwc3: Remove WQ_MEM_RECLAIM flag while allocating sm_usb_wq

This change removes WQ_MEM_RECLAIM flag while allocating workqueue for
sm_usb_wq. With this flag, below warning message and calltrace is seen
while flushing hub_wq during peripheral disconnect.

[  223.260116] workqueue: WQ_MEM_RECLAIM k_sm_usb:dwc3_otg_sm_work is
flushing !WQ_MEM_RECLAIM usb_hub_wq:          (null)
[  223.279836] pstate: 60c00005 (nZCv daif +PAN +UAO)
[  223.304544] pc : check_flush_dependency+0x118/0x120
[  223.393801] lr : check_flush_dependency+0x118/0x120
Call trace:
[  224.069750]  check_flush_dependency+0x118/0x120
[  224.074420]  flush_workqueue+0x1b0/0x488
[  224.078466]  usb_flush_hub_wq+0x18/0x20
[  224.082416]  usb_remove_hcd+0xc4/0x240
[  224.086288]  xhci_plat_remove+0x68/0xe8
[  224.090244]  platform_drv_remove+0x28/0x50
[  224.094463]  device_release_driver_internal+0x1ac/0x260
[  224.099839]  device_release_driver+0x24/0x30
[  224.104244]  bus_remove_device+0xf0/0x140
[  224.108379]  device_del+0x294/0x4a0
[  224.111974]  platform_device_unregister+0x30/0xa0
[  224.116817]  dwc3_host_exit+0x5c/0x68
[  224.120589]  dwc3_otg_start_host+0x37c/0x760
[  224.124983]  dwc3_otg_sm_work+0x2d4/0x718
[  224.129112]  process_one_work+0x328/0x6b0
[  224.133247]  worker_thread+0x330/0x4d0
[  224.137108]  kthread+0x128/0x138
[  224.140437]  ret_from_fork+0x10/0x1c
[  224.144116] irq event stamp: 0.

Change-Id: Ida3f8c56406756b09cfb81f816e8ea76e21f8caa
Signed-off-by: Pratham Pratap <prathampratap@codeaurora.org>