hw/acpi/microvm: turn on 8042 bit in FADT boot architecture flags if present

hw/acpi/microvm: turn on 8042 bit in FADT boot architecture flags if present

The second bit of IAPC_BOOT_ARCH in FADT table indicates the presence of
keyboard controller implemented as 8042 or equivalent micro controller. This
change enables this flag for microvms if such a device exists (for example,
when added explicitly from the QEMU commandline). Change
654701e292d98b308b0 ("hw/acpi: add indication for i8042 in IA-PC boot flags of the FADT table")
enabled this flag for i386 q35 based machines. The reason for doing the same
for micro-vms is to make sure we provide the correct tables to the guest OS
uniformly in all cases when an i8042 device is present. When this bit is not
enabled, guest OSes has to find other indirect methods to detect the device
which we would like to avoid.

Signed-off-by: Ani Sinha <ani@anisinha.ca>
Message-Id: <20220304154032.2071585-5-ani@anisinha.ca>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>