avr32: add some more at91 to cpu.h definition

Somme common drivers will need those at91 cpu_is_xxx() definitions.
Those definitions are already in Linus' tree so if we want to use them
in common drivers, we will need them in AVR32 cpu.h file.

Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Acked-by: Hans-Christian Egtvedt <hans-christian.egtvedt@atmel.com>