msdk: allow user build this plugin against MFX version 2.2+ (oneVPL)

msdk: allow user build this plugin against MFX version 2.2+ (oneVPL)

Intel oneVPL SDK (oneVPL) is a successor to Intel Media SDK (MSDK)[1].
User may use -Dmfx_api=MSDK or -Dmfx_api=oneVPL to specify the required
SDK when building this plugin. If the SDK is not specified, meson will
try MSDK firstly, then oneVPL if MSDK is not available

Version 2.2+ is required in this patch because pkg-config file was not
provided officially before version 2.2

[1]https://spec.oneapi.com/versions/latest/elements/oneVPL/source/appendix/VPL_intel_media_sdk.html

Part-of: <https://gitlab.freedesktop.org/gstreamer/gst-plugins-bad/-/merge_requests/1503>