In NetbufTrim() function, the NetBuf TotalSize should be checked with 0 before making the trim operation, otherwise the function will fall into infinite loop. Contributed-under: TianoCore Contribution Agreement 1.0 Signed-off-by: Fu Siyuan <siyuan.fu@intel.com> Reviewed-by: Wu Jiaxin <jiaxin.wu@intel.com>