usb: host: oxu210hp-hcd: remove set but not used variables 'uframes, transfer_buffer_length'

Fixes gcc '-Wunused-but-set-variable' warning:

drivers/usb/host/oxu210hp-hcd.c: In function 'scan_periodic':
drivers/usb/host/oxu210hp-hcd.c:2256:13: warning:
 variable 'uframes' set but not used [-Wunused-but-set-variable]

drivers/usb/host/oxu210hp-hcd.c: In function 'oxu_urb_enqueue':
drivers/usb/host/oxu210hp-hcd.c:2835:6: warning:
 variable 'transfer_buffer_length' set but not used [-Wunused-but-set-variable]

They are never used since introduction.

Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>