net: usb: Merge cpu_to_le32s + memcpy to put_unaligned_le32

Merge the combo uses of cpu_to_le32s and memcpy.
Use put_unaligned_le32 instead.
This simplifies the code.

Signed-off-by: Chuhong Yuan <hslester96@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>