ata: fix sparse warnings in sata_mv.c

pp is never used again in this function, no need to declare a
new one.

drivers/ata/sata_mv.c:1545:24: warning: symbol 'pp' shadows an earlier one
drivers/ata/sata_mv.c:1501:22: originally declared here
drivers/ata/sata_mv.c:1553:24: warning: symbol 'pp' shadows an earlier one
drivers/ata/sata_mv.c:1501:22: originally declared here

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