dt-bindings: bridge: samsung-dsim: Make some flags optional

In the event a device is connected to the samsung-dsim
controller that doesn't support the burst-clock, the
driver is able to get the requested pixel clock from the
attached device or bridge.  In these instances, the
samsung,burst-clock-frequency isn't needed, so remove
it from the required list.

The pll-clock frequency can be set by the device tree entry
for samsung,pll-clock-frequency, but in some cases, the
pll-clock may have the same clock rate as sclk_mipi clock.
If they are equal, this flag is not needed since the driver
will use the sclk_mipi rate as a fallback.

Signed-off-by: Adam Ford <aford173@gmail.com>
Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
Reviewed-by: Fabio Estevam <festevam@gmail.com>
Reviewed-by: Jagan Teki <jagan@amarulasolutions.com>
Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20230528132727.3933-1-aford173@gmail.com

Documentation/devicetree/bindings/display/bridge/samsung,mipi-dsim.yaml

@@ -70,7 +70,9 @@ properties:
   samsung,burst-clock-frequency:
     $ref: /schemas/types.yaml#/definitions/uint32
     description:
-      DSIM high speed burst mode frequency.
+      DSIM high speed burst mode frequency.  If absent,
+      the pixel clock from the attached device or bridge
+      will be used instead.
 
   samsung,esc-clock-frequency:
     $ref: /schemas/types.yaml#/definitions/uint32
@@ -80,7 +82,8 @@ properties:
   samsung,pll-clock-frequency:
     $ref: /schemas/types.yaml#/definitions/uint32
     description:
-      DSIM oscillator clock frequency.
+      DSIM oscillator clock frequency. If absent, the clock frequency
+      of sclk_mipi will be used instead.
 
   phys:
     maxItems: 1
@@ -134,9 +137,7 @@ required:
   - compatible
   - interrupts
   - reg
-  - samsung,burst-clock-frequency
   - samsung,esc-clock-frequency
-  - samsung,pll-clock-frequency
 
 allOf:
   - $ref: ../dsi-controller.yaml#