dt-bindings: clock: brcm,kona-ccu: convert to YAML

Convert Broadcom Kona family clock controller unit (CCU) bindings
to DT schema.

Changes during conversion:
- remove "dmac" from clock-output-names for brcm,bcm11351-master-ccu,
such a clock doesn't exist
- remove "uartb4" from clock-output-names for brcm,bcm21664-slave-ccu,
such a clock doesn't exist

Signed-off-by: Stanislav Jakubek <stano.jakubek@gmail.com>
Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://lore.kernel.org/r/ZVED01t3+coBd44x@standask-GA-A55M-S2HP
Signed-off-by: Stephen Boyd <sboyd@kernel.org>