net/mlx5e: Fix wrong bitwise comparison usage in macsec_fs_rx_add_rule function

The cited commit produces a sparse check error of type
"sparse: error: restricted __be64 degrades to integer". The
offending line wrongly did a bitwise operation between two different
storage types one of 64 bit when the other smaller side is 16 bit
which caused the above sparse error, furthermore bitwise operation
usage here is wrong in the first place as the constant MACSEC_PORT_ES
is not a bitwise field.

Fix by using the right mask to get the lower 16 bit if the sci number,
and use comparison operator '==' instead of bitwise '&' operator.

Fixes: 3b20949c

 ("net/mlx5e: Add MACsec RX steering rules")
Signed-off-by: Raed Salem <raeds@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>
Link: https://lore.kernel.org/r/20221026135153.154807-15-saeed@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>