ARM: at91: fix at91_extern_irq usage for non-dt boards

Since 4b68520dc0ec96153bc0d87bca5ffba508edfcf
ARM: at91: add AIC5 support

we allocate the at91_extern_irq.

This patch makes it static and stores the non-dt extern irq in the soc
structure. It is then possible to use a at91_get_extern_irq() function
to get the value for outside of the irq driver. It is useful for passing
its value to at91_aic_init().

Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
Acked-by: Ludovic Desroches <ludovic.desroches@atmel.com>
[nicolas.ferre@atmel.com: rework commit message]
Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>
ARM: at91: cpuidle: Fix target_residency

The following commit:

commit 7e348b9012522fa0efd854d20d210d5e57fcedd1
Author: Robert Lee <rob.lee@linaro.org>
Date:   Tue Mar 20 15:22:43 2012 -0500

    ARM: at91: Consolidate time keeping and irq enable

    Enable core cpuidle timekeeping and irq enabling and remove that
    handling from this code.

introduced an additional zero to the state1 (suspend) target residency.

With a periodic tick, the cpu never enters the state1 with both 10000 and
100000.

With a tickless system, it enters to state1 much more often with the
initial value, roughly x7 more.

Fix it by setting the value to 10ms again.

Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
[nicola.ferre@atmel.com: add precisions given by Daniel to commit message]
Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>
ARM: at91/PMC: sama5d3 family doesn't have a PLLB

Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>
ARM: at91/PMC: at91sam9n12 family has a PLLB

Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>
ARM: at91/PMC: fix at91sam9n12 USB FS init

at91sam9n12 has Full-speed only USB. So we should add
it to the list in at91_pllb_usbfs_clock_init() function.
Moreover, at91sam9n12 has an unusual PMC in the sense that it
has a PLLB but also has a USB clock register.

Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>
ARM: at91/PMC: use at91_usb_rate() for UTMI PLL

We are using this function, now that we have introduced
the support for UTMI clock for computing the USB host rate.

Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>