Add support for changing clock rate and parent clock for Armada 37xx
peripheral clocks.
Only clocks which can be disabled (.can_gate is true) can have parent
or rate changed.
This is needed so that Turris Mox can change SPI clock in device tree.
Signed-off-by: Marek Behun <marek.behun@nic.cz>
Signed-off-by: Stefan Roese <sr@denx.de>