EDAC, sb_edac: Fix TAD presence check for sbridge_mci_bind_devs()

EDAC, sb_edac: Fix TAD presence check for sbridge_mci_bind_devs()

In commit

  7d375bffa524 ("sb_edac: Fix support for systems with two home agents per socket")

NUM_CHANNELS was changed to 8 and the channel space was renumerated to
handle EN, EP, and EX configurations.

The *_mci_bind_devs() functions - except for sbridge_mci_bind_devs() -
got a new device presence check in the form of saw_chan_mask. However,
sbridge_mci_bind_devs() still uses the NUM_CHANNELS for loop.

With the increase in NUM_CHANNELS, this loop fails at index 4 since
SB only has 4 TADs.  This results in the following error on SB machines:

  EDAC sbridge: Some needed devices are missing
  EDAC sbridge: Couldn't find mci handler
  EDAC sbridge: Couldn't find mci handle

This patch adapts the saw_chan_mask logic for sbridge_mci_bind_devs() as
well.

After this patch:

  EDAC MC0: Giving out device to module sbridge_edac.c controller Sandy Bridge Socket#0: DEV 0000:3f:0e.0 (POLLED)
  EDAC MC1: Giving out device to module sbridge_edac.c controller Sandy Bridge Socket#1: DEV 0000:7f:0e.0 (POLLED)

Signed-off-by: Seth Jennings <sjenning@redhat.com>
Acked-by: Aristeu Rozanski <aris@redhat.com>
Acked-by: Tony Luck <tony.luck@intel.com>
Tested-by: Borislav Petkov <bp@suse.de>
Cc: <stable@vger.kernel.org> # v4.2
Cc: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
Cc: linux-edac <linux-edac@vger.kernel.org>
Link: http://lkml.kernel.org/r/1438798561-10180-1-git-send-email-sjenning@redhat.com
Signed-off-by: Borislav Petkov <bp@suse.de>