usb: core: hcd: change sizeof(vaddr) to sizeof(unsigned long)

usb: core: hcd: change sizeof(vaddr) to sizeof(unsigned long)

`vaddr` is a pointer to unsigned char. sizeof(vaddr) here intends
to get the size of a pointer. But readers may get confused. Change
sizeof(vaddr) to sizeof(unsigned long) makes more sense.

Suggested-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Guo Zhengkui <guozhengkui@vivo.com>
Link: https://lore.kernel.org/r/20211209062441.9856-1-guozhengkui@vivo.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>