ShellPkg: Fix ifconfig hang issue with incomplete parameters

ShellPkg: Fix ifconfig hang issue with incomplete parameters

This patch is used to fix ifconfig hang issue with incomplete
parameters. In addition, some error related output information
is added to increase the interactivity.

Cc: Leekha Shaveta <shaveta@freescale.com>
Cc: Carsey Jaben <jaben.carsey@intel.com>
Cc: Ye Ting <ting.ye@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Jiaxin Wu <jiaxin.wu@intel.com>
Reviewed-by: Jaben Carsey <jaben.carsey@intel.com>
Tested-by: Leekha Shaveta <shaveta@freescale.com>
git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@19212 6f19259b-4bc3-4df7-8a09-765794883524