ARM: at91: add AIC5 support

The number of lines of AIC5 has increased from 32 to 128. Due to this
increase, a source select register has been introduced for the interrupt
line selection. Moreover, register mapping has been changed. For that reasons,
we need some dedicated callbacks for AIC5.
Power management is also concerned by these changes. On suspend, we can't get
the whole interrupt mask register as before, we have to read this register 128
times. To reduce this overhead, a snapshot of the whole IMR is maintained.

Signed-off-by: Ludovic Desroches <ludovic.desroches@atmel.com>
Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>