remoteproc: remoteproc debugfs file fixes

Don't bother checking the remoteproc state before calling
rproc_trigger_recovery() because that function will verify the
state, and the state can only be safely checked while holding the
mutex anyway.

Make the mode for "recovery" be writable.

Signed-off-by: Alex Elder <elder@linaro.org>
Link: https://lore.kernel.org/r/20200228183359.16229-3-elder@linaro.org


Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>