net/sfc: prepare EF10 Rx event parser to be reused
net/sfc: prepare EF10 Rx event parser to be reused

Equal stride super-buffer Rx mode will be handled by the dedicated
Rx datapath and the mode has almost the same Rx event structure as
single packet Rx mode.

Restructure the code to allow the common parts to be shared.

Signed-off-by: Andrew Rybchenko <ac94ab2a8fe9a9a087f6e24dcbc16626b52c07e8@solarflare.com>
Reviewed-by: Ivan Malov <436a2feb05eb79a6862681e66bd0193220e8fb2d@oktetlabs.ru>
Reviewed-by: Andy Moreton <adbee5d9b6a6a553b71b14302d03837591e26c9d@solarflare.com>

john-mcnamara-intel/dpdk,john-mcnamara-intel/dpdk,john-mcnamara-intel/dpdk,john-mcnamara-intel/dpdk