SecurityPkg Variable: Update code in ProcessVariable () to

SecurityPkg Variable: Update code in ProcessVariable () to

check IsDeleteAuthVariable () first and then check
UserPhysicalPresent () to avoid the case below.

PcdSetXX (a DynamicHii PCD) -> gRT->SetVariable ()
-> UserPhysicalPresent () -> PcdGetXX ()

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Star Zeng <star.zeng@intel.com>
Reviewed-by: Jiewen Yao <jiewen.yao@intel.com>
git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@17058 6f19259b-4bc3-4df7-8a09-765794883524