acpi: aml: add helper for Opcode Arg2 Arg2 [Dst] AML pattern

Currently AML API doesn't compose terms in form of
following pattern:

   Opcode Arg2 Arg2 [Dst]

but ASL used in piix4/q35 DSDT ACPI tables uses that
form, so for clean conversion of it, AML API should
be able to handle an optional 'Dst' argumet used there.

Since above pattern is used by arithmetic/bit ops,
introduce helper that they could reuse.
It reduces code duplication in existing 5 aml_foo()
functions and also will prevent more duplication
when exiting functions are extended to support
optional 'Dst' argument.

Signed-off-by: Igor Mammedov <imammedo@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Marcel Apfelbaum <marcel@redhat.com>
Reviewed-by: Shannon Zhao <shannon.zhao@linaro.org>
