ShellPkg/ifconfig: Update help message

Couple of instances had IP4 mentioned, instead of IPv4.
Changing all to IPv4 to maintain consistency.

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Hegde Nagaraj P <nagaraj-p.hegde@hpe.com>
Reviewed-by: Tapan Shah <tapandshah@hpe.com>
Reviewed-by: Jaben Carsey <jaben.carsey@intel.com>
Reviewed-by: Wu Jiaxin <jiaxin.wu@intel.com>
(cherry picked from commit c1f4b86ba786cc9cbe5c88a05abc9bf0554b1cc8)
1 file changed