usb: gadget: composite: Fix bMaxPower for SuperSpeedPlus

commit c724417b upstream.

SuperSpeedPlus peripherals must report their bMaxPower of the
configuration descriptor in units of 8mA as per the USB 3.2
specification. The current switch statement in encode_bMaxPower()
only checks for USB_SPEED_SUPER but not USB_SPEED_SUPER_PLUS so
the latter falls back to USB 2.0 encoding which uses 2mA units.
Replace the switch with a simple if/else.

Fixes: eae5820b ("usb: gadget: composite: Write SuperSpeedPlus config descriptors")
Signed-off-by: Jack Pham <jackp@codeaurora.org>
Signed-off-by: Felipe Balbi <balbi@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>