feat(nic): add an additional validation to the mcast flag to the MAC CHECK subcomponent of RX MAC

This prevents the BCAST and MCAST flags from being set simultaneously in the output (meta)data.

Author: xmarus09

comp/nic/mac_lite/rx_mac_lite/comp/mac_check/mac_check.vhd

@@ -224,7 +224,7 @@ begin
 
     mac_cast_err_g : for r in 0 to REGIONS-1 generate
         -- Possible multicast error occurence
-        s_multicast_err(r) <= not s_ext_mac_arr(r)(0);
+        s_multicast_err(r) <= (not s_ext_mac_arr(r)(0)) or not s_broadcast_err(r);
         -- Possible broadcast error occurence
         s_broadcast_err(r) <= nand s_ext_mac_arr(r);
     end generate;