Add a driver for the PMC clocks of the at91sam9260, at91sam9261,
at91am9263 and at91sam9g20 SoCs.
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
[sboyd@kernel.org: Make i signed to fix signedness bug]
Signed-off-by: Stephen Boyd <sboyd@kernel.org>