ata: make ata_port::fastdrain_cnt *unsigned int*

*unsigned long* ata_port::fastdrain_cnt (64-bit value in a 64-bit kernel)
is always assigned from the 32-bit *unsigned int* variables, thus could
also be made just *unsigned int*...
Signed-off-by: Sergey Shtylyov <s.shtylyov@omp.ru>
Signed-off-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>

include/linux/libata.h

@@ -847,7 +847,7 @@ struct ata_port {
 	enum ata_lpm_policy	target_lpm_policy;
 
 	struct timer_list	fastdrain_timer;
-	unsigned long		fastdrain_cnt;
+	unsigned int		fastdrain_cnt;
 
 	async_cookie_t		cookie;