Define sam9x5 clocks in sam9x5 dt files and make use of them in peripheral
definitions.
Signed-off-by: NBoris BREZILLON <boris.brezillon@free-electrons.com>
Acked-by: NAlexandre Belloni <alexandre.belloni@free-electrons.com>
Signed-off-by: NNicolas Ferre <nicolas.ferre@atmel.com>

Alias was missing for SoC of the at91sam9x5 familly that embed USART3.
Reported-by: NJiri Prchal <jiri.prchal@aksignal.cz>
[b.brezillon@overkiz.com: advised to place changes in at91sam9x5_usart3.dtsi]
Acked-by: NBoris BREZILLON <b.brezillon@overkiz.com>
Signed-off-by: NNicolas Ferre <nicolas.ferre@atmel.com>

This patch splits the sam9x5 peripheral definitions into:
- a common base for all sam9x5 SoCs (at91sam9x5.dtsi)
- several optional peripheral definitions which will be included by specific
  sam9x5 SoCs (at91sam9x5_'periph name'.dtsi)

This provides a better representation of the real hardware (drop unneeded
dt nodes) and avoids future peripheral id conflict (lcdc and isi both use
peripheral id 25).
Signed-off-by: NBoris BREZILLON <b.brezillon@overkiz.com>
Signed-off-by: NNicolas Ferre <nicolas.ferre@atmel.com>