pata_sis: mark most const data static as well

This pushes timing and other values into preinitialized read-only data
sections rather than being inlined into the code. None of these
functions are called more than a handful of times, so reducing code size
makes sense.

Signed-off-by: Dan McGee <dpmcgee@gmail.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>