drm/bridge/synopsys: dsi: move phy_ops callbacks around panel enablement

If implementation-specific phy_ops need to be defined they probably
should be enabled before trying to talk to the panel and disabled only
after the panel was disabled.

Right now they are enabled last and disabled first, so might make it
impossible to talk to some panels - example for this being the px30
with an external Innosilicon dphy that needs the phy to be enabled
to transfer commands to the panel.

So move the calls appropriately.

changed in v5:
- rebased on top of 5.5-rc1
- merged with dsi timing change to prevent ordering conflicts

Signed-off-by: Heiko Stuebner <heiko.stuebner@theobroma-systems.com>
Reviewed-by: Neil Armstrong <narmstrong@baylibre.com>
Tested-by: Yannick Fertre <yannick.fertre@st.com>
Reviewed-by: Philippe Cornu <philippe.cornu@st.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191209143130.4553-3-heiko@sntech.de