clocksource/drivers/oxnas: Fix OX820 compatible

[ Upstream commit fbc87aa0f7c429999dc31f1bac3b2615008cac32 ]

The OX820 compatible is wrong is the driver, fix it.

Fixes: 2ea3401e ("clocksource/drivers/oxnas: Add OX820 compatible")
Reported-by: Daniel Golle <daniel@makrotopia.org>
Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>