usb: gadget: g_ffs: Adjust f_ffs[0] allocation type

usb: gadget: g_ffs: Adjust f_ffs[0] allocation type

In preparation for making the kmalloc family of allocators type aware,
we need to make sure that the returned type from the allocation matches
the type of the variable being assigned. (Before, the allocator would
always return "void *", which can be implicitly cast to any pointer type.)

The assigned type is "struct usb_function **" but the returned type
will be "struct usb_function ***". These are the same size allocation
(pointer size), but different types. Adjust the allocation type to match
the assignment.

Signed-off-by: Kees Cook <kees@kernel.org>
Link: https://lore.kernel.org/r/20250426062125.work.209-kees@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>