ixgbe: fix masking of bits read from IXGBE_VXLANCTRL register

In ixgbe_clear_udp_tunnel_port(), we read the IXGBE_VXLANCTRL register
and then try to mask some bits out of the value, using the logical
instead of bitwise and operator.

Fixes: a21d0822

 ("ixgbe: add support for geneve Rx offload")
Signed-off-by: Sabrina Dubroca <sd@queasysnail.net>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>