Patch from Randolph Chung, slightly modified by rmk.

When displaying the details of memory mapped serial ports, we want to show
some sane base value.  The cookie returned from ioremap can be meaningless
to users (and developers), especially when the cookie could be a dynamically
allocated virtual address.

The more useful cookie is the value passed into ioremap.  We already have
support for handling this cookie internally - we haven't allowed the PCI
probe module to hand it to the higher levels until now.