net: dsa: mv88e6xxx: remove 88E6185 G2 interrupt

The 88E6185 family has no Global 2 Interrupt Source or Mask registers.
Remove the MV88E6XXX_FLAG_G2_INT from MV88E6XXX_FLAGS_FAMILY_6185.

Signed-off-by: Vivien Didelot <vivien.didelot@savoirfairelinux.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>