arm64: KVM: add trap handlers for AArch32 debug registers

arm64: KVM: add trap handlers for AArch32 debug registers

Add handlers for all the AArch32 debug registers that are accessible
from EL0 or EL1. The code follow the same strategy as the AArch64
counterpart with regards to tracking the dirty state of the debug
registers.

Reviewed-by: Anup Patel <anup.patel@linaro.org>
Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
(cherry picked from commit bdfb4b389c8d8f07e2d5b8e1291e01c789ba4aad)
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>