dt-bindings: display: samsung,amoled-mipi-dsi: Do not require enable-gpios on samsung...

dt-bindings: display: samsung,amoled-mipi-dsi: Do not require enable-gpios on samsung,s6e63j0x03

The samsung,s6e63j0x03 does not have enable GPIO, so do not require it.
This fixes dtbs_check warning:

  arch/arm/boot/dts/exynos3250-rinato.dt.yaml: panel@0: 'enable-gpios' is a required property

Acked-by: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
Link: https://lore.kernel.org/r/20200829172532.29358-1-krzk@kernel.org
Signed-off-by: Rob Herring <robh@kernel.org>