Now that the infrastructure to handle erratum 1165522 is in place,
let's make it a selectable option and add the required documentation.
Reviewed-by: NJames Morse <james.morse@arm.com>
Signed-off-by: NMarc Zyngier <marc.zyngier@arm.com>
Signed-off-by: NWill Deacon <will.deacon@arm.com>