EDAC: Add scrub control feature

Add a scrub control to manage memory scrubbers in the system.

Devices with a scrub feature register with the EDAC device driver which
retrieves the scrub descriptor from the scrub driver and exposes the
control attributes for a instance to userspace at

  /sys/bus/edac/devices/<dev-name>/scrubX/.

The common sysfs scrub control interface abstracts the control of
arbitrary scrubbing functionality into a common set of functions. The
attribute nodes are only present if the client driver has implemented
the corresponding attribute callback function and passed the operations
to the device driver during registration.

  [ bp: Massage commit message, docs and code, simplify text a bit.
    Integrate fixup for: https://lore.kernel.org/r/202502251009.0sGkolEJ-lkp@intel.com


Reported-by: kernel test robot <lkp@intel.com>
    Reported-by: Dan Carpenter <dan.carpenter@linaro.org> ]

Co-developed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Shiju Jose <shiju.jose@huawei.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Tested-by: Daniel Ferguson <danielf@os.amperecomputing.com>
Tested-by: Fan Ni <fan.ni@samsung.com>
Link: https://lore.kernel.org/r/20250212143654.1893-3-shiju.jose@huawei.com