The check for a non-null parent_name is always true as there is an
earlier check for a null parent_name that returns -ENODEV. Remove this
redundant check and always set init.num_parents to 1.

Detected by CoverityScan CID#1309477 ("Logically dead code")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>