sata_nv: Add CPB register info to error_handler output

sata_nv: Add CPB register info to error_handler output

When error handling occurs with pending commands, output the contents
of the next CPB count and next CPB index registers as well as the others,
since these may be useful for debugging.

Signed-off-by: Robert Hancock <hancockr@shaw.ca>
Signed-off-by: Jeff Garzik <jeff@garzik.org>