ARM: at91: introduce OLD_IRQ_AT91 Kconfig option

Introduce the OLD_IRQ_AT91 Kconfig option to prepare migration to the
new AIC driver.

Select this option for all at91 SoCs and all available boards so that we
can later move DT enabled boards to the new irq driver and keep the old
implementation when legacy boards are selected.

Signed-off-by: Boris BREZILLON <boris.brezillon@free-electrons.com>
Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>
ARM: at91: enclose at91_aic_xx calls in IS_ENABLED(CONFIG_OLD_IRQ_AT91) blocks

Enclose at91_aic_xx calls in IS_ENABLED(CONFIG_OLD_IRQ_AT91) blocks in
order to prepare migration to the new AIC driver.

In the new AIC driver the suspend/resume functions are called by the
generic irq framework and are no longer needed in the PM specific code.

Moreover, the new AIC driver no longer exposes the at91_aic_base variable
which is used by the at91_aic_read functions.

Signed-off-by: Boris BREZILLON <boris.brezillon@free-electrons.com>
Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>
ARM: at91: make use of the new AIC driver for dt enabled boards

Remove selection of OLD_IRQ_AT91 when selecting dt boards.
Select ATMEL_AIC_IRQ for sama5 SoCs (a kernel compiled for this SoC will
always use ATMEL_AIC_IRQ driver).
Select ATMEL_AIC_IRQ for at91rm9200 and at91sam9 SoCs only if OLD_IRQ_AT91
is not selected (which means we are compiling a pure DT kernel, without
any legacy board support).

Remove specific irq init code in all dt board files: this init procedure
is automatically handled in of_irq_init which is called by the arm irq core
code and is in charge of calling the appropriate aic init functions.

Signed-off-by: Boris BREZILLON <boris.brezillon@free-electrons.com>
Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>
ARM: at91: remove old irq material

Remove all the material related to AIC5 support: this interrupt controller
driver is now implemented in drivers/irqchip/atmel-aic.c.

Signed-off-by: Boris BREZILLON <boris.brezillon@free-electrons.com>
Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>