usb: gadget: composite: fill bcdUSB for any gadget max speed

When handling device GET_DESCRIPTOR, composite gadget driver fills
the bcdUSB field only if the gadget supports USB 3.0. Otherwise
the field is left unfilled.

For consistency, set bcdUSB to 0x0200 for gadgets that don't
support superspeed.

It's correct to use 0x0200 for any setting that doesn't use
superspeed, since USB 2.0 devices can restrict themselves to
full speed only. It is NOT correct to use 0x0210, since BOS
descriptors are handled only if gadget_is_superspeed() is
satisfied, otherwise it results in a stall.

Signed-off-by: Igor Kotrasinski <i.kotrasinsk@samsung.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>