ARM: dts: Drop custom clkctrl compatible and update omap4 l4per

We can now use the clock-output-names and don't need custom compatible
values for each clkctrl instance. And we can use a generic name also for
the clock manager instance.

Cc: Stephen Boyd <sboyd@kernel.org>
Cc: Tero Kristo <kristo@kernel.org>
Signed-off-by: Tony Lindgren <tony@atomide.com>
Message-Id: <20220204084339.12341-3-tony@atomide.com>