Revert "ANDROID: modpost: Forbid double exports"

This reverts commit 479488f5.

It was merged in a different way upstream in 5.19-rc1, so drop it now to
allow the merge to be clean.

Bug: 174214891
Cc: Quentin Perret <qperret@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
Change-Id: I127ccf87a4cd8b0ace0dc83e69458ccc64eb66ac