net/sfc: bind EvQ DMA space to EvQ type and type-local index

net/sfc: bind EvQ DMA space to EvQ type and type-local index

The index of an event queue index is computed from the index of the
corresponding transmit or receive queue, and depends on the total
number of receive queues. As a consequence, the index of an event
queue bound to a transmit queue changes if the total number of
receive queues is changed.

Fixes: 58294ee65afb ("net/sfc: support event queue")
Cc: stable@dpdk.org
Signed-off-by: Andrew Rybchenko <arybchenko@solarflare.com>
Reviewed-by: Andy Moreton <amoreton@solarflare.com>