remoteproc: Pass type of shutdown to subdev remove

remoteproc instances can be stopped either by invoking shutdown or by an
attempt to recover from a crash. For some subdev types it's expected to
clean up gracefully during a shutdown, but are unable to do so during a
crash - so pass this information to the subdev remove functions.

Acked-By: Chris Lew <clew@codeaurora.org>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>