Add support for boost-up register of usb251xb hub.
boost-up property control USB electrical drive strength
This register can be set:

 - Normal mode -> 0x00
 - Low         -> 0x01
 - Medium      -> 0x10
 - High        -> 0x11

(Normal Default)

References:
 - http://www.mouser.com/catalog/specsheets/2514.pdf p29
Reviewed-by: Richard Leitner <richard.leitner@linux.dev>
Signed-off-by: Tommaso Merciai <tomm.merciai@gmail.com>
Link: https://lore.kernel.org/r/20220128181713.96856-1-tomm.merciai@gmail.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>