ANDROID: GKI: usb: gadget: support claiming indexed endpoints by name

Partial cherry-pick of commit ee9b63c156e1 ("Give unique name to gsi
endpoints") to support claiming an endpoint by name that has been
prefixed with an index.

Bug: 174539520
Change-Id: I3d6e9a3f9eb3fd0c445afc3b76f28dc9199374f4
Signed-off-by: Hemant Kumar <hemantk@codeaurora.org>
(cherry picked from commit ee9b63c156e12ea607b4eb00d80256ce8218ddcb)
Signed-off-by: Will McVicker <willmcvicker@google.com>