UPSTREAM: usb: raw-gadget: improve uapi headers comments

Fix typo "trasferred" => "transferred".

Don't call USB requests URBs.

Fix comment style.

Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Signed-off-by: Felipe Balbi <balbi@kernel.org>
Bug: 147413187
(cherry picked from commit 17ff3b72e742192f11e3136174ac4eafb50e38d4)
Change-Id: Idd35454a469266d1921096293f4c3c6a51ea034f
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>