PCI: leave MEM and IO decoding disabled during 64-bit BAR sizing, too

After 253d2e54, we disable MEM and IO decoding for most devices while we
size 32-bit BARs.  However, we restore the original COMMAND register before
we size the upper 32 bits of 64-bit BARs, so we can still cause a conflict.

This patch waits to restore the original COMMAND register until we're
completely finished sizing the BAR.

Reference: https://lkml.org/lkml/2007/8/25/154


Acked-by: Jacob Pan <jacob.jun.pan@linux.intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>