EDAC/sysfs: Remove csrow objects on errors

All created csrow objects must be removed in the error path of
edac_create_csrow_objects(). The objects have been added as devices.

They need to be removed by doing a device_del() *and* put_device() call
to also free their memory. The missing put_device() leaves a memory
leak. Use device_unregister() instead of device_del() which properly
unregisters the device doing both.

Fixes: 7adc05d2 ("EDAC/sysfs: Drop device references properly")
Signed-off-by: Robert Richter <rrichter@marvell.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Tested-by: John Garry <john.garry@huawei.com>
Cc: <stable@vger.kernel.org>
Link: https://lkml.kernel.org/r/20200212120340.4764-4-rrichter@marvell.com