Building for X86_32 produces shift count warnings, so use BIT_64() to
eliminate the warnings.

drivers/edac/mce_amd.c:778: warning: left shift count >= width of type
drivers/edac/mce_amd.c:778: warning: left shift count >= width of type
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Cc: Doug Thompson <dougthompson@xmission.com>
Cc: bluesmoke-devel@lists.sourceforge.net
Signed-off-by: Borislav Petkov <borislav.petkov@amd.com>