The Command register in the PCI config space has some read-only bits.
Any writes to those bits should be masked out.
Signed-off-by: NAmit Shah <amit.shah@redhat.com>
Signed-off-by: NAurelien Jarno <aurelien@aurel32.net>

git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@6092 c046a42c-6fe2-441c-8c8c-71466251a162