Make libOmxVdec build with VNDK

When the vndk is enabled (BOARD_VNDK_VERSION=current),
vendor libraries must only link against vendor variants
in the build system. This also means that they receive
restricted sets of headers and that automatic global
headers are restricted.

A static library moved to being vendor is a build
time only change for libOmxVidcCommon.

Dependency to libgui was removed since libgui is not available to
vendors and the dependency was bogus.

media_plugin_header are explicitly added since global include path isn't
available when BOARD_VNDK_VERSION is on.

Test: mma with BOARD_VNDK_VERSION=current
Bug: 69526027
Change-Id: Icb326660fbb90f39396fb2108bfc06e9fb72a93d