thermal: rcar_thermal: Handle probe error gracefully

[ Upstream commit 39056e8a989ef52486e063e34b4822b341e47b0e ]

If the common register memory resource is not available the driver needs
to fail gracefully to disable PM. Instead of returning the error
directly store it in ret and use the already existing error path.

Signed-off-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Link: https://lore.kernel.org/r/20200310114709.1483860-1-niklas.soderlund+renesas@ragnatech.se


Signed-off-by: Sasha Levin <sashal@kernel.org>