SecurityPkg/SecurityPkg.dec: Update TcgPpVendorLib.h to Tcg2PpVendorLib.h
    
    Tcg2PpVendorLib library class header should be
    Include/Library/Tcg2PpVendorLib.h instead of
    Include/Library/TcgPpVendorLib.h.
    https://bugzilla.tianocore.org/show_bug.cgi?id=2146
    
    Cc: Jiewen Yao <jiewen.yao@intel.com>
    Cc: Jian Wang <jian.j.wang@intel.com>
    Cc: Chao Zhang <chao.b.zhang@intel.com>
    Signed-off-by: Shenglei Zhang <shenglei.zhang@intel.com>
    Reviewed-by: Jian J Wang <jian.j.wang@intel.com>
    Reviewed-by: Liming Gao <liming.gao@intel.com>
    Reviewed-by: Chao Zhang <chao.b.zhang@intel.com>