e752x_edac: Drop pvt->bridge_ck

pvt->bridge_ck always points to the same device as pvt->dev_d0f1, so
get rid of the former and only use the latter.

Signed-off-by: Jean Delvare <jdelvare@suse.de>
Tested-by: Aristeu Rozanski <aris@redhat.com>
Link: http://lkml.kernel.org/r/20140224151544.16ba28a0@endymion.delvare
Cc: Mark Gross <mark.gross@intel.com>
Cc: Doug Thompson <dougthompson@xmission.com>
Signed-off-by: Borislav Petkov <bp@suse.de>