ata: fix sparse warning in pata_cs5536.c

Everybody passes in a u32...why fight it.

drivers/ata/pata_cs5536.c:124:26: warning: incorrect type in argument 3 (different signedness)
drivers/ata/pata_cs5536.c:124:26:    expected int *val
drivers/ata/pata_cs5536.c:124:26:    got unsigned int *<noident>

Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>