Revert "media: mc: Add num_links flag to media_pad"

This reverts commit cff51913 which is
commit baeddf94 upstream.

It breaks the Android kernel abi and can be brought back in the future
in an abi-safe way if it is really needed.

Bug: 161946584
Change-Id: I5b874c8b01bdd8cdeed6dec216fdad500593f5a7
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>