const_structs.checkpatch: add phy_ops

All usages of phy_ops in include/linux uses const phy_ops * and all
instances of phy_ops in the kernel that are not const already can be made
const (patches have been posted for those separately).

Suggested-by: Joe Perches <joe@perches.com>
Signed-off-by: Rikard Falkeborn <rikard.falkeborn@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Kishon Vijay Abraham I <kishon@ti.com>
Cc: Vinod Koul <vkoul@kernel.org>
Link: https://lkml.kernel.org/r/20200824214132.9072-1-rikard.falkeborn@gmail.com


Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>