kernel: package ramoops pstore-ram crash log storage

Package the ability to log kernel crashes to 'ramoops' pstore
files into RAM in /sys/fs/pstore

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



The files in RAM survive a warm reboot, but not a cold reboot.

Note: kmod-ramoops selects kmod-pstore and kmod-reed-solomon.

The feature can be used by selecting the kmod-ramoops and
adding a ramoops reserved-memory definition to the device DTS.
Example from R7800:

       reserved-memory {
                rsvd@5fe00000 {
                        reg = <0x5fe00000 0x200000>;
                        reusable;
                };

                ramoops@42100000 {
                        compatible = "ramoops";
                        reg = <0x42100000 0x40000>;
                        record-size = <0x4000>;
                        console-size = <0x4000>;
                        ftrace-size = <0x4000>;
                        pmsg-size = <0x4000>;
                };
        };

If no definition has been made in DTS, no crash log is stored
for the device.

Signed-off-by: Hannu Nyman <hannu.nyman@iki.fi>
Signed-off-by: Christian Lamparter <chunkeey@gmail.com>
(added CONFIG_EFI_VARS_PSTORE disable)