soundwire: fix alignment issues in header files

use Linux style
Reviewed-by: NTakashi Iwai <tiwai@suse.de>
Signed-off-by: NPierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>