EDAC/amd8131: Remove defined but not used bridge_str

Fix the following gcc warning:

  drivers/edac/amd8131_edac.c:47:21: warning: ‘bridge_str’ defined but not
  used [-Wunused-const-variable=]
   static char * const bridge_str[] = {
                       ^~~~~~~~~~

Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Jason Yan <yanaijie@huawei.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Robert Richter <rrichter@marvell.com>
Link: https://lkml.kernel.org/r/20200415085006.6732-1-yanaijie@huawei.com