hw/arm/virt-acpi-build: Generate FADT table and update ACPI headers

hw/arm/virt-acpi-build: Generate FADT table and update ACPI headers

In the case of mach virt, it is used to set the Hardware Reduced bit
and enable PSCI SMP booting through HVC. So ignore FACS and FADT
points to DSDT.

Update the header definitions for FADT taking into account the new
additions of ACPI v5.1 in `include/hw/acpi/acpi-defs.h`

Signed-off-by: Shannon Zhao <[email protected]>
Signed-off-by: Shannon Zhao <[email protected]>
Message-id: 1432522520[email protected]
Signed-off-by: Peter Maydell <[email protected]>