remoteproc: modify rproc_handle_carveout to support pre-registered region

In current version rproc_handle_carveout() function registers carveout
for allocation.
This patch extends rproc_handle_carveout() function to support
pre-registered region. Match is done on region name, then requested
device address and length are checked.
If match found, pre-registered region is associated with resource
table request.
If no name match found, new carveout is registered for allocation.

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