KVM: arm64: Use common debug sysreg definitions

Now that we have common definitions for the debug register encodings,
make the KVM code use these, simplifying the sys_reg_descs table.

The table previously erroneously referred to MDCCSR_EL0 as MDCCSR_EL1.
This is corrected (as is necessary in order to use the common sysreg
definition).

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Christoffer Dall <christoffer.dall@linaro.org>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: kvmarm@lists.cs.columbia.edu