1) Update code to use PcdFixedUsbCredentialProviderTokenFileName and PcdMaxVaria...

1)      Update code to use PcdFixedUsbCredentialProviderTokenFileName and PcdMaxVariableSize as patchable PCD instead of FixedAtBuild PCD.
2)      Correct a typo in file comments of Tpm12Ownership.c

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Dong, Guo <guo.dong@intel.com>
Reviewed-by: Gao, Liming <liming.gao@intel.com>
Reviewed-by: Yao, Jiewen <jiewen.yao@intel.com>
git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@15811 6f19259b-4bc3-4df7-8a09-765794883524