vpl: Ensure all VPL symbols in Kconfig have some VPL dependency

Tighten up symbol dependencies in a number of places.  Ensure that a VPL
specific option has at least a direct dependency on VPL.  In places
where it's clear that we depend on something more specific, use that
dependency instead.

Reported-by: Pali Rohár <pali@kernel.org>
Signed-off-by: Tom Rini <trini@konsulko.com>