USB: gadget: acm,rndis: IAD class, subclass & prot should match 1st iface

USB: gadget: acm,rndis: IAD class, subclass & prot should match 1st iface

Microsoft recommends that the class and subclass fields of
an IAD match the same fields from the first interface in the
collection that the IAD is grouping. In practice, we are also
finding that the protocol fields should also match. Without
this change, the default Microsoft composite driver may not
group interfaces properly, which is what allows child
function drivers with IAD's to load correctly.

Signed-off-by: Mike Lockwood <lockwood@android.com>