host1x: Convert to bus methods

host1x: Convert to bus methods

The callbacks .probe(), .remove() and .shutdown() for device_drivers
should go away. So migrate to bus methods. There are two differences
that need addressing:

 - The bus remove callback returns void while the driver remove callback
   returns int (the actual value is ignored by the core).
 - The bus shutdown callback is also called for unbound devices, so an
   additional check for dev->driver != NULL is needed.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@baylibre.com>
Tested-by: Luca Ceresoli <luca.ceresoli@bootlin.com> # tegra20 tegra-video
Reviewed-by: Luca Ceresoli <luca.ceresoli@bootlin.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>
Link: https://patch.msgid.link/dd55d034c68953268ea416aa5c13e41b158fcbb4.1765355236.git.u.kleine-koenig@baylibre.com