MIPS/OCTEON/ata: Convert pata_octeon_cf.c to use device tree.

MIPS/OCTEON/ata: Convert pata_octeon_cf.c to use device tree.

The patch needs to eliminate the definition of OCTEON_IRQ_BOOTDMA so
that the device tree code can map the interrupt, so in order to not
temporarily break things, we do a single patch to both the interrupt
registration code and the pata_octeon_cf driver.

Also rolled in is a conversion to use hrtimers and corrections to the
timing calculations.

Acked-by: Jeff Garzik <jgarzik@redhat.com>
Signed-off-by: David Daney <david.daney@cavium.com>