firmware: mub: Add CN10K memory test configuration utility

commit 44b555b04adb0059779b9dcd9740398044a26f55 from
git@git.assembla.com:cavium/WindRiver.linux.git

Following change add simple sysfs interface that enables users
to configure memory subsystem POST (DRAM).

The module creates entries in /sys/bus/mub/devices/memtest directory:
  - reboot, configures scope of testing for next warm reset
  - power_on, configures scope of testing for next cold boot
  - mem_length, configures memory length under test

Allowed values for test types are 'none', 'nominal' and 'extended'.
First value stands for no test, later for normal scope testing.
The last value is used for extended testing (takes extra time).
The scope and range of tests depends on platform.

The memory length is expressed in megabytes.
Top value is 4294967294 MB. When 4294967295 MB is set,
the whole DRAM will be tested skipping the user preserved memory area.

Signed-off-by: Wojciech Bartczak <wbartczak@marvell.com>
Change-Id: I2ff418009ddc0d6c8b1a51ff8288c03324708bee
Reviewed-on: https://sj1git1.cavium.com/c/IP/SW/kernel/linux/+/78515


Reviewed-by: Chandrakala Chavva <cchavva@marvell.com>
Tested-by: sa_ip-sw-jenkins <sa_ip-sw-jenkins@marvell.com>
Reviewed-on: https://sj1git1.cavium.com/c/IP/SW/kernel/linux/+/120332


Reviewed-by: Sunil Kovvuri Goutham <sgoutham@marvell.com>
Signed-off-by: Ruiqiang Hao <Ruiqiang.Hao@windriver.com>