remoteproc: Cache resource table size

We don't re-read the resource table during a recovery, so it is possible
in the recovery path that the resource table has a different size than
cached_table. Store the original size of cached_table to avoid these
getting out of sync.

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>