[PATCH] sata_mv: grab host lock inside eng_timeout

Bug fix:  mv_eng_timeout() calls mv_err_intr() without first grabbing the host lock,
which can lead to all sorts of interesting scenarios.

This whole error-handling portion of sata_mv is nasty (and will get fixed for
the new EH stuff), but for now this patch will help keep it on life-support.

Signed-off-by: Mark Lord <liml@rtr.ca>
Signed-off-by: Jeff Garzik <jeff@garzik.org>