[PATCH] sata_mv: prevent unnecessary double-resets

The mv_err_intr() function is invoked from the driver's interrupt handler,
as well as from the timeout function.  This patch prevents it from triggering
a one-after-the-other double reset of the controller when invoked
from the timeout function.

This also adds a check for a timeout race condition that has been observed
to occur with this driver in earlier kernels.  This should not be needed,
in theory, but in practice it has caught bugs.  Maybe nuke it at a later date.

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