ENOTSUPP is not a SUSV4 error code, prefer EOPNOTSUPP.

Reviewed-by: Krzysztof Kozlowski <krzk@kernel.org>
Signed-off-by: Bongsu Jeon <bongsu.jeon@samsung.com>
Link: https://lore.kernel.org/r/20201117081137epcms2p84b5dd8d84ca608f44b0bb722b48f50b1@epcms2p8


Signed-off-by: Jakub Kicinski <kuba@kernel.org>