ARM: fiq_debugger: fix multiple consoles and make it a preferred console

Fix setting up consoles on multiple fiq debugger devices by
splitting the tty driver init into the initcall, and initializing
the single tty device during probe.  Has the side effect of moving
the tty device node to /dev/ttyFIQx, where x is the platform device
id, which should normally match the serial port.

To avoid having to pass a different console=/dev/ttyFIQx for every
device, make the fiq debugger a preferred console that will be used
by default if no console was passed on the command line.

Change-Id: I6cc2670628a41e84615859bc96adba189966d647
Signed-off-by: Colin Cross <ccross@android.com>