driver core: faux: Quiet probe failures

The acpi-einj conversion to faux_device_create() leads to a noisy error
message when the error injection facility is disabled. Quiet the error as
CXL error injection via ACPI expects the module to stay loaded even if the
error injection facility is disabled.

This situation arose because CXL knows proper kernel named objects to
trigger errors against, but acpi-einj knows how to perform the error
injection. The injection mechanism is shared with non-CXL use cases. The
result is CXL now has a module dependency on einj-core.ko, and init/probe
failures are handled at runtime.

Fixes: 6cb9441bfe8d ("ACPI: APEI: EINJ: Transition to the faux device interface")
Signed-off-by: Dan Williams <[e-mail]>
Reviewed-by: Jonathan Cameron <[e-mail]>
Acked-by: Greg Kroah-Hartman <[e-mail]>
Link: https://patch.msgid.link/[e-mail]
Signed-off-by: Rafael J. Wysocki <[e-mail]>

drivers/base/faux.c

···
 	 * successful is almost impossible to determine by the caller.
 	 */
 	if (!dev->driver) {
-		dev_err(dev, "probe did not succeed, tearing down the device\n");
+		dev_dbg(dev, "probe did not succeed, tearing down the device\n");
 		faux_device_destroy(faux_dev);
 		faux_dev = NULL;
 	}