qapi: make string output visitor parse int list

Signed-off-by: Hu Tao <hutao@cn.fujitsu.com>
qom: introduce object_property_get_enum and object_property_get_uint16List

Signed-off-by: Hu Tao <hutao@cn.fujitsu.com>
qmp: add query-memdev

Add qmp command query-memdev to query for information
of memory devices

Signed-off-by: Hu Tao <hutao@cn.fujitsu.com>
hmp: add info memdev

This is the hmp counterpart of qmp query-memdev.

Signed-off-by: Hu Tao <hutao@cn.fujitsu.com>