powerpc/eeh: Cleanup on EEH PCI address cache

The patch does cleanup on EEH PCI address cache based on the fact
EEH core is the only user of the component.

        * Cleanup on function names so that they all have prefix
          "eeh" and looks more short.
        * Function printk() has been replaced with pr_debug() or
          pr_warning() accordingly.

Signed-off-by: Gavin Shan <shangw@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>