net/dim: Rename *_get_profile() functions to *_get_rx_moderation()

Preparation for introducing adaptive TX to net DIM.

Signed-off-by: Tal Gilboa <talgi@mellanox.com>
Reviewed-by: Tariq Toukan <tariqt@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>