ix: no reason to enable interrupts that we don't know how to handle

[Mike Belopuhov]

we don't do intel i/oat and don't set up parameters for the
tcp timer interrupts,  therefore there's no reason we should
enable the interrupt itself.

ok?

diff --git dev/pci/ixgbe_type.h dev/pci/ixgbe_type.h
index 601c6d5..b592222 100644
--- dev/pci/ixgbe_type.h
+++ dev/pci/ixgbe_type.h
@@ -1318,7 +1318,6 @@
 #define IXGBE_EIMS_ENABLE_MASK ( \
                                 IXGBE_EIMS_RTX_QUEUE       | \
                                 IXGBE_EIMS_LSC             | \
-                                IXGBE_EIMS_TCP_TIMER       | \
                                 IXGBE_EIMS_OTHER)
 
 /* Immediate Interrupt Rx (A.K.A. Low Latency Interrupt) */