clk: bcm63xx-gate: add BCM6318 support

Add support for the gated clock controllers found on the BCM6318.

Signed-off-by: Álvaro Fernández Rojas <noltari@gmail.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Link: https://lore.kernel.org/r/20200610140858.207329-3-noltari@gmail.com


Signed-off-by: Stephen Boyd <sboyd@kernel.org>