drm/rockchip: lvds: Hide scary error messages on probe deferral

Commit 52d11c86 ("drm/rockchip: lvds: do not print scary message when
probing defer") already started hiding scary messages that are not relevant
if the requested supply just returned EPROBE_DEFER, but there are more
possible sources - like the phy.

So modernize the whole logging in the probe path by replacing the
remaining deprecated DRM_DEV_ERROR with appropriate dev_err(_probe)
and drm_err calls.

The distinction here is that all messages talking about mishaps of the
lvds element use dev_err(_probe) while messages caused by interaction
with the main Rockchip drm-device use drm_err.

Reviewed-by: Andy Yan <andy.yan@rock-chips.com>
Signed-off-by: Heiko Stuebner <heiko.stuebner@cherry.de>
Reviewed-by: Quentin Schulz <quentin.schulz@cherry.de>
Signed-off-by: Heiko Stuebner <heiko@sntech.de>
Link: https://patchwork.freedesktop.org/patch/msgid/20250304124418.111061-3-heiko@sntech.de