drivers: base: add description for .coredump() callback

Commit 3c47d19ff4dc ("drivers: base: add coredump driver ops") added
a new callback in struct device_driver, but not a kerneldoc description
so here it is.

Fixes: 3c47d19ff4dc ("drivers: base: add coredump driver ops")
Signed-off-by: Arend van Spriel <aspriel@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

include/linux/device.h

@@ -256,6 +256,7 @@ enum probe_type {
  *		automatically.
  * @pm:		Power management operations of the device which matched
  *		this driver.
+ * @coredump:	Called through sysfs to initiate a device coredump.
  * @p:		Driver core's private data, no one other than the driver
  *		core can touch this.
  *