Define the kernel crash log storage ramoops/pstore feature
for R7800 and its sister XR500.

Reference to the ramoops admin guide in upstream Linux:
https://www.kernel.org/doc/html/v5.10/admin-guide/ramoops.html



Tested with R7800.

Signed-off-by: Hannu Nyman <hannu.nyman@iki.fi>