ARM: dts: omap: Drop ti,omap36xx compatible

This was not matched anywhere and provides no additional information. The
driver code already checks also for "ti,omap3630" compatible.

Signed-off-by: Andrew Davis <afd@ti.com>
Message-Id: <20230216153339.19987-2-afd@ti.com>
[tony@atomide.com: updated comments for ti,omap3630 compatible]
Signed-off-by: Tony Lindgren <tony@atomide.com>