The ACPI code requires to use global variables in order to collect
information from the tables.

For now, a single global variable is used, but more will be added in a
subsequent patch. To make clear they are ACPI specific, gather all the
information in a single structure.
Signed-off-by: NJulien Grall <julien.grall@arm.com>
Acked-by: NChristofer Dall <christoffer.dall@linaro.org>
Acked-by: NHanjun Guo <hanjun.guo@linaro.org>
Signed-off-by: NChristoffer Dall <christoffer.dall@linaro.org>