serial: fit blackfin uart over sport driver into common uart infrastructure

Fit blackfin uart over sport driver into common uart inftrastructure.  It
is based on the early platform interfaces to get the platform data early
when the console is initilized.

1. Enable sport uart driver to change uart baud, data bit, stop bit at
   runtime.  Bind the index of uart device nodes to physical index of
   sports.

2. Move all platform data into arch specific board files.  Register
   and probe platform device data in both early and normal stages.

3. Console is registered in sport uart driver as well.

4. Remove 500 us block waiting in sport tx stop code by putting a
   dummy data into tx fifo to make sure the sport tx stops when all bytes
   are shifted out except for the dummy data.

5. clean up a bit and fix up coding style.

Signed-off-by: Sonic Zhang <sonic.zhang@analog.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Mike Frysinger <vapier@gentoo.org>
Cc: Bryan Wu <cooloney@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>