SecurityPkg: Tcg2Dxe: Update PCR[4] measure logic

SecurityPkg: Tcg2Dxe: Update PCR[4] measure logic

Update PCR[4] measure logic for each boot attempt.
1. Measure event to PCR[4] instead of PCR[5]
2. Measure “Calling UEFI Application from Boot Option”
http://www.trustedcomputinggroup.org/wp-content/uploads/PC-ClientSpecific_Platform_Profile_for_TPM_2p0_Systems_v21.pdf

Cc: Star Zeng <star.zeng@intel.com>
Cc: Yao Jiewen <jiewen.yao@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Chao Zhang <chao.b.zhang@intel.com>
Reviewed-by: Yao Jiewen <jiewen.yao@intel.com>