hw/arm/smmuv3: Add GBPA register

hw/arm/smmuv3: Add GBPA register

GBPA register can be used to globally abort all
transactions.

It is described in the SMMU manual in "6.3.14 SMMU_GBPA".
ABORT reset value is IMPLEMENTATION DEFINED, it is chosen to
be zero(Do not abort incoming transactions).

Other fields have default values of Use Incoming.

If UPDATE is not set, the write is ignored. This is the only permitted
behavior in SMMUv3.2 and later.(6.3.14.1 Update procedure)

As this patch adds a new state to the SMMU (GBPA), it is added
in a new subsection for forward migration compatibility.
GBPA is only migrated if its value is different from the reset value.
It does this to be backward migration compatible if SW didn't write
the register.

Signed-off-by: Mostafa Saleh <smostafa@google.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Eric Auger <eric.auger@redhat.com>
Message-id: 20230214094009.2445653-1-smostafa@google.com
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>