This patch adds a ppc64 implementation of the routine providing
the list of default 8250 serial ports. It provides a empty list
by default unless the platform code fills it, and it provides
a generic function for user by Open Firmware based machines which
fills the list based on serial ports found in the OF device-tree.

It depends on the previous patch adding the generic support for
this to the 8250 driver.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>