net/usb: r8152: Use module_usb_driver()

module_usb_driver() eliminates boilerplate and simplifies the code.

Signed-off-by: Sachin Kamat <sachin.kamat@linaro.org>
Cc: Realtek linux nic maintainers <nic_swsd@realtek.com>
Signed-off-by: David S. Miller <davem@davemloft.net>