Patch from Dan Williams

Convert old-style serial devices to platform devices so that printk's are visible during the boot process.
Signed-off-by: NDan Williams <dan.j.williams@intel.com>
Signed-off-by: NDeepak Saxena <dsaxena@plexity.net>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>