ixgbe: resolve shift of negative value warning

Make use of GENMASK instead of open coding the equivalent operation
incorrectly.
Signed-off-by: Jacob Keller <jacob.e.keller@intel.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

drivers/net/ethernet/intel/ixgbe/ixgbe_main.c

@@ -3766,9 +3766,9 @@ static void ixgbe_configure_virtualization(struct ixgbe_adapter *adapter)
 	reg_offset = (VMDQ_P(0) >= 32) ? 1 : 0;
 
 	/* Enable only the PF's pool for Tx/Rx */
-	IXGBE_WRITE_REG(hw, IXGBE_VFRE(reg_offset), (~0) << vf_shift);
+	IXGBE_WRITE_REG(hw, IXGBE_VFRE(reg_offset), GENMASK(vf_shift, 31));
 	IXGBE_WRITE_REG(hw, IXGBE_VFRE(reg_offset ^ 1), reg_offset - 1);
-	IXGBE_WRITE_REG(hw, IXGBE_VFTE(reg_offset), (~0) << vf_shift);
+	IXGBE_WRITE_REG(hw, IXGBE_VFTE(reg_offset), GENMASK(vf_shift, 31));
 	IXGBE_WRITE_REG(hw, IXGBE_VFTE(reg_offset ^ 1), reg_offset - 1);
 	if (adapter->bridge_mode == BRIDGE_MODE_VEB)
 		IXGBE_WRITE_REG(hw, IXGBE_PFDTXGSWC, IXGBE_PFDTXGSWC_VT_LBEN);