net: ipa: check table memory regions earlier

Verify that the sizes of the routing and filter table memory regions
are valid as part of memory initialization, rather than waiting for
table initialization.  The main reason to do this is that upcoming
patches use these memory region sizes to determine the number of
entries in these tables, and we'll want to know these sizes are good
sooner.

Signed-off-by: Alex Elder <elder@linaro.org>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>