bridge: drop reference to unused option embedded from manpage

bridge: drop reference to unused option embedded from manpage

While looking at the manpage, I noticed a reference to 'embedded' that was
added by this commit:

	commit d611682a8c8f28205158e6d3a7d5e2d01db022cc
	Author: John Fastabend <john.r.fastabend@intel.com>
	Date:   Thu Sep 13 23:50:36 2012 -0700

	    iproute2: bridge: finish removing replace option in man pages

I no longer see any reference to the 'embedded' option in any c- or h-files, so
it seems worthwhile to remove.

Signed-off-by: Andy Gospodarek <gospo@cumulusnetworks.com>
CC: John Fastabend <john.r.fastabend@intel.com>