modules: unexport __module_text_address

commit 3fe1e56d0e68b623dd62d8d38265d2a052e7e185 upstream.

__module_text_address is only used by built-in code.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jessica Yu <jeyu@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>