ixgbevf: minor cleanups for ixgbevf_set_itr()

ixgbevf: minor cleanups for ixgbevf_set_itr()

Orabug: 23177316

adapter->rx_itr_setting is not a mask so check it with == instead of &
do not default to 12K interrupts in ixgbevf_set_itr()

There should be no functional effect from these changes.

Signed-off-by: Emil Tantilov <emil.s.tantilov@intel.com>
Tested-by: Phil Schmitt <phillip.j.schmitt@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
(cherry picked from commit 9ad3d6f7eb300d464bfce2c80e7b1594f5e5eff9)
Signed-off-by: Brian Maly <brian.maly@oracle.com>
Conflicts:
	drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c