PCI hotplug: shpchp: don't blindly claim non-AMD 0x7450 device IDs

Previously we claimed device ID 0x7450, regardless of the vendor, which is
clearly wrong.  Now we'll claim that device ID only for AMD.

I suspect this was just a typo in the original code, but it's possible this
change will break shpchp on non-7450 AMD bridges.  If so, we'll have to fix
them as we find them.

Reference: http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=638863


Reported-by: Ralf Jung <ralfjung-e@gmx.de>
Cc: Joerg Roedel <joerg.roedel@amd.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>