pci: Remove redundant alignment of BAR size

Size of a BAR is naturally aligned so there is no need
to align it explicitly.

Cc: Thomas Huth <thuth@redhat.com>
Cc: Andrew Jones <drjones@redhat.com>
Signed-off-by: Alexander Gordeev <agordeev@redhat.com>
Signed-off-by: Andrew Jones <drjones@redhat.com>