usb: gadget: unconditionally allocate hs/ss descriptor in bind operation

Take f_midi_bind() for example,  when composite layer call it, it will
allocate hs descriptor by calling gadget_is_dualspeed() API to check
gadget max support speed capability, but most other gadget function didn't
do like this.

To follow other function drivers, it is safe to remove the check which
mean support all possible link speed by default in function driver.

Similar change apply to midi2 and uvc.

Also in midi and midi2, as there is no descriptor difference between
super speed and super speed plus, follow other gadget function drivers,
do not allocate descriptor for super speed plus, composite layer will
handle it properly.

Signed-off-by: Linyu Yuan <quic_linyyuan@quicinc.com>
Link: https://lore.kernel.org/r/20230803091053.9714-5-quic_linyyuan@quicinc.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>