remoteproc: Reset table_ptr on stop

The installed resource table is no longer accessible after stopping the
remote, so update table_ptr to point to the local copy.

Reviewed-By: Loic Pallardy <loic.pallardy@st.com>
Tested-By: Loic Pallardy <loic.pallardy@st.com>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>