drm: Move struct drm_device.hose to legacy section

drm: Move struct drm_device.hose to legacy section

The field is only relevant for legacy DRM drivers. Its only non-legacy
user in the DRM core is in drm_file.c. This code is now protected by
CONFIG_DRM_LEGACY. Radeon, the only driver that used the field, has been
changed to maintain it's own copy.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Christian König <christian.koenig@amd.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210112081035.6882-7-tzimmermann@suse.de