libata: make ata_port_type const

Make this const as it is only stored in the const field of a device
structure. Make the declaration in header const too.

Structure found using Coccinelle and changes done by hand.

Signed-off-by: Bhumika Goyal <bhumirks@gmail.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
2 files changed