remoteproc: Introduce function rproc_detach()

Introduce function rproc_detach() to enable the remoteproc
core to release the resources associated with a remote processor
without stopping its operation.

Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Reviewed-by: Arnaud Pouliquen <arnaud.pouliquen@st.com>
Link: https://lore.kernel.org/r/20210312162453.1234145-11-mathieu.poirier@linaro.org


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