Address the issue of EDAC/BIOS coexistence for the e752x chip-sets.

We have found a problem where the BIOS will start the system with the error
registers (dev0:fun1) hidden and assuming it has exclusive access to them.
The edac driver violates this assumption.

The workaround this patch offers is to honor the hidden-ness as an
indication that it is not safe to use those registers.
Signed-off-by: NMark Gross <mark.gross@intel.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>