usb: xhci: Change MAX_HC_PORTS to 255

HCSPARAMS1:MaxPorts field specifies the maximum port number value,
and its valid values are in the range of 1 to 255.

Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Stefan Roese <sr@denx.de>
Tested-by: Stefan Roese <sr@denx.de>
1 file changed