staging: greybus: remove empty callback function

staging: greybus: remove empty callback function

Remove the optional remove callback for the soc_codec_dev_gbaudio
structure. The only place it is referenced is
snd_soc_component_remove() which is only called if the sound_component
pointer is non-null. The null function pointers here can be optionally
ommitted. When a sound component is registered this way, the remove
callback is optional. We can safely remove the whole gbcodec_remove
function, which used to be an empty function with a void return type.

Suggested-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Jaehee Park <jhpark1013@gmail.com>
Link: https://lore.kernel.org/r/12037ae2502ad7d0311bcdf2178c3d2156293236.1649824370.git.jhpark1013@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>