Variable err is assigned -ENOMEM followed by an error return path via label
err_udev that does not access the variable and returns with the -ENOMEM
error return code. The assignment to err is redundant and can be removed.

Link: https://lore.kernel.org/r/20210327230650.25803-1-colin.king@canonical.com
Addresses-Coverity: ("Unused value")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>