ACPICA: Parser: Allow method invocations as target operands

ACPICA: Parser: Allow method invocations as target operands

ACPICA commit a6cca7a4786cdbfd29cea67e84b5b01a8ae6ff1c

Method invocations as target operands are allowed as target
operands in the ASL grammar. This change implements support
for this. Method must return a reference for this to work
properly at runtime, however.

Link: https://github.com/acpica/acpica/commit/a6cca7a4
Signed-off-by: Bob Moore <robert.moore@intel.com>
Signed-off-by: Lv Zheng <lv.zheng@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>