SecurityPkg/Tcg: Fix debug messages

SecurityPkg/Tcg: Fix debug messages

Debug messages are using a format strings with %s for
a Unicode string, but the strings being printed are
ASCII strings and this results in corrupted debug
messages.  Change the the format string to use %a
instead of %s.

Cc: Chao Zhang <chao.b.zhang@intel.com>
Cc: Jiewen Yao <jiewen.yao@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Michael Kinney <michael.d.kinney@intel.com>
Reviewed-by: Jiewen Yao <jiewen.yao@intel.com>
Reviewed-by: Chao Zhang <chao.b.zhang@intel.com>
git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@19617 6f19259b-4bc3-4df7-8a09-765794883524