drm/mipi-dsi: stop passing non struct drm_device to drm_err() and friends

The expectation is that the struct drm_device based logging helpers get
passed an actual struct drm_device pointer rather than some random
struct pointer where you can dereference the ->dev member.

Convert drm_err(host, ...) to dev_err(host->dev, ...). This matches
current usage, as struct drm_device is not available, but drops "[drm]
*ERROR*" from logs.

Reviewed-by: Simona Vetter <simona.vetter@ffwll.ch>
Reviewed-by: Luca Ceresoli <luca.ceresoli@bootlin.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/842f97ade87d6f0c4b1de12e8ed5610a1b07fd8c.1737644530.git.jani.nikula@intel.com