ethdev: fix flow rule copy functions

ethdev: fix flow rule copy functions

The corrupted code checks only RAW flow item type special case for
returning its size but doesn't deal with any other flow item type
and returns 0 for all the others.

This bug leaves the flow descriptor empty for non RAW types.

The fix takes the correct size to any regular types from appropriate
array.

The same issue, with a similar fix, is in flow action size method
which deals only with RSS special type.

This bug was already present in the original code taken from testpmd.

Fixes: 18da437b5f63 ("ethdev: add flow rule copy function")

Signed-off-by: Matan Azrad <matan@mellanox.com>
Acked-by: Adrien Mazarguil <adrien.mazarguil@6wind.com>