clk: at91: add sama5d3 pmc driver

Add a driver for the PMC clocks of the sama5d3.

Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Link: https://lkml.kernel.org/r/20200110223033.1261791-1-alexandre.belloni@bootlin.com


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