Originally there was an ifdef case to handle when no debug uart
was selected. In commit 0ea12930
that case was removed which causes the following build failure,

linux-2.6/arch/arm/kernel/debug.S: Assembler messages:
linux-2.6/arch/arm/kernel/debug.S:174: Error: bad instruction `addruart r1,r2'
linux-2.6/arch/arm/kernel/debug.S:176: Error: bad instruction `waituart r2,r3'
linux-2.6/arch/arm/kernel/debug.S:177: Error: bad instruction `senduart r1,r3'
linux-2.6/arch/arm/kernel/debug.S:178: Error: bad instruction `busyuart r2,r3'
linux-2.6/arch/arm/kernel/debug.S:190: Error: bad instruction `addruart r1,r2'

This is a partial revert to add back the case which was removed with
two caveats. First the API for the addruart macro was updated, and
the new addruart case now return 0xfff00000 so that a know IO mapping
is created instead of a random one.

Cc: Jeremy Kerr <jeremy.kerr@canonical.com>
Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Cc: Jason Wang <jason77.wang@gmail.com>
Cc: Tony Lindgren <tony@atomide.com>
Cc: Nicolas Pitre <nico@fluxnic.net>
Cc: Russell King - ARM Linux <linux@arm.linux.org.uk>
Signed-off-by: Daniel Walker <dwalker@codeaurora.org>