ata_host_suspend() always returns 0, so the result checks in many drivers
look pointless.  Let's make this function return *void* instead of *int*.

Found by Linux Verification Center (linuxtesting.org) with the SVACE static
analysis tool.
Signed-off-by: NSergey Shtylyov <s.shtylyov@omp.ru>
Acked-by: NUwe Kleine-König <u.kleine-koenig@pengutronix.de>
Reviewed-by: NHannes Reinecke <hare@suse.de>
Signed-off-by: NDamien Le Moal <damien.lemoal@opensource.wdc.com>