igb: Drop unnecessary write of E1000_IMS from igb_msix_other

igb: Drop unnecessary write of E1000_IMS from igb_msix_other

Since we mask interrupts in EIMS not in IMS there is no need to re-enable
mask bits in that register.  As such we can remove the write to IMS from
the end of igb_msix_other.

(cherry picked from commit 9ab64ba3c74540cfb8716232834df486bcc6120d)
Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
Tested-by:  Aaron Brown  <aaron.f.brown@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: Joe Jin <joe.jin@oracle.com>