Merge patch series "usb: gadget: Refactor function drivers to use __free() cleanup"

Kuen-Han Tsai <khtsai@google.com> says:

This patch series refactors the error-handling paths in the bind()
function for f_ncm, f_acm, f_ecm, and f_rndis drivers.

The current, unified goto logic in these drivers is vulnerable to a null
pointer dereference. This is caused by the cleanup logic incorrectly
handling the stale usb_request pointer after a bind/unbind cycle. This
series fixes this issue by converting the drivers to use the modern
__free() scope-based cleanup mechanism.

Patches 1-2 are preparatory, adding the endpoint pointer to struct
usb_request and defining helpers for the __free() cleanup. The remaining
four patches use this new plumbing to refactor each driver.

Future work
-----------
1. Refactor usb_ep_free_request(), usb_ep_queue(), and usb_ep_dequeue()
   functions as the ep parameter becomes redudant.
2. Convert the remaining gadget function drivers to use the new __free()
   cleanup mechanism.

Link: https://lore.kernel.org/r/20250916-ready-v1-0-4997bf277548@google.com


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>