PR modula2/116557: Remove physical address from COPYING.FDL

This patch removes the physical address from the COPYING.FDL and
replaces it with a URL.

gcc/m2/ChangeLog:

	PR modula2/116557
	* COPYING.FDL: Remove physical address and replace with a URL.

Signed-off-by: Gaius Mulley <gaiusmod2@gmail.com>