ipvlan: remove h from printk format specifier

ipvlan: remove h from printk format specifier

This change fixes the checkpatch warning described in this commit
commit cbacb5ab0aa0 ("docs: printk-formats: Stop encouraging use of
  unnecessary %h[xudi] and %hh[xudi]")

Standard integer promotion is already done and %hx and %hhx is useless
so do not encourage the use of %hh[xudi] or %h[xudi].

Cleanup output to use __func__ over explicit function strings.

Signed-off-by: Tom Rix <trix@redhat.com>
Link: https://lore.kernel.org/r/20210124190804.1964580-1-trix@redhat.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>