net: ipa: clean up interconnect initialization

Pass an the address of an IPA interconnect structure and its
configuration data to ipa_interconnect_init_one() and have that
function initialize all the structure's fields.  Change the function
to simply return an error code.

Introduce ipa_interconnect_exit_one() to encapsulate the cleanup of
an IPA interconnect structure.

Signed-off-by: Alex Elder <elder@linaro.org>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>