drm/bridge: tc358768: always enable HS video mode

Always enable HS video mode setting the TXMD bit, without this change no
video output is present with DSI sinks that are setting
MIPI_DSI_MODE_LPM flag (tested with LT8912B DSI-HDMI bridge).

Previously the driver was enabling HS mode only when the DSI sink was
not explicitly setting the MIPI_DSI_MODE_LPM, however this is not
correct.

The MIPI_DSI_MODE_LPM is supposed to indicate that the sink is willing
to receive data in low power mode, however clearing the
TC358768_DSI_CONTROL_TXMD bit will make the TC358768 send video in
LP mode that is not the intended behavior.

Fixes: ff1ca639 ("drm/bridge: Add tc358768 driver")
Signed-off-by: Francesco Dolcini <francesco.dolcini@toradex.com>
Reviewed-by: Robert Foss <rfoss@kernel.org>
Signed-off-by: Robert Foss <rfoss@kernel.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20230427142934.55435-2-francesco@dolcini.it

drivers/gpu/drm/bridge/tc358768.c

@@ -867,8 +867,7 @@ static void tc358768_bridge_pre_enable(struct drm_bridge *bridge)
 	val = TC358768_DSI_CONFW_MODE_SET | TC358768_DSI_CONFW_ADDR_DSI_CONTROL;
 	val |= (dsi_dev->lanes - 1) << 1;
 
-	if (!(dsi_dev->mode_flags & MIPI_DSI_MODE_LPM))
-		val |= TC358768_DSI_CONTROL_TXMD;
+	val |= TC358768_DSI_CONTROL_TXMD;
 
 	if (!(mode_flags & MIPI_DSI_CLOCK_NON_CONTINUOUS))
 		val |= TC358768_DSI_CONTROL_HSCKMD;