Add functions to modify and delete qos responsible for mapping eth queues
to event queues used for configuring event Rx adapter.
The mbox functions have been moved from octeontx_pkivf.c to
octeontx_pkivf.h to allow event_octeontx to access them.
Signed-off-by: Pavan Nikhilesh <pbhagavatula@caviumnetworks.com>
