amd64_edac: Fix incorrect wraparounds

amd64_edac: Fix incorrect wraparounds

dct_base and dct_limit obtain 32 bit register values when they read
their respective pci config space registers. A left shift beyond 32 bits
will cause them to wrap around. Similar case for chan_addr as can be
seen from the bug report (link below). In the patch, we rectify this by
casting chan_addr to u64 and by comparing dct_base and dct_limit against
properly shifted sys_addr in order to compare the correct bits.

Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Aravind Gopalakrishnan <Aravind.Gopalakrishnan@amd.com>
Link: http://lkml.kernel.org/r/20130819132302.GA12171@elgon.mountain
Signed-off-by: Borislav Petkov <bp@suse.de>