ice: Suppress false-positive style issues reported by static analyzer

A recent version of cppcheck falsely reports-
    Variable ip.hdr is assigned a value that is never used.

ip is a union so the pointer ip.hdr is actually used when referenced as
ip.v4 and ip.v6.  Silence these false reports when using cppcheck with the
--inline-suppr command-line option.

Signed-off-by: Bruce Allan <bruce.w.allan@intel.com>
Signed-off-by: Anirudh Venkataramanan <anirudh.venkataramanan@intel.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>