Smatch complains that "len" could be larger than the sizeof(value)
so we could be copying garbage here. I have changed this to match
how things are done in composite_setup().
The call tree looks like:
composite_setup()
--> f_audio_setup()
--> audio_get_intf_req()
composite_setup() expects the return value to be set to
sizeof(value).
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> Signed-off-by: Felipe Balbi <balbi@ti.com>