CryptoPkg: Fix possible unresolved external symbol issue.

The compiler (visual studio) may optimize some explicit strcmp call
in openssl source to use the intrinsic memcmp call.
In CrtLibSupport.h, we just use #define to mapping memcmp to
CompareMem API. So in Link phase, this kind of intrinsic optimization
will cause the "unresolved external symbol" error. For example:
    OpensslLib.lib(v3_utl.obj) : error LNK2001:
                               unresolved external symbol _memcmp

This patch will keep the memcmp mapping, and provide extra Intrinsic
memcmp wrapper to satisfy the symbol link.

Cc: Ting Ye <ting.ye@intel.com>
Cc: Feng Tian <feng.tian@intel.com>
Cc: Laszlo Ersek <lersek@redhat.com>
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Qin Long <qin.long@intel.com>
Reviewed-by: Laszlo Ersek <lersek@redhat.com>

CryptoPkg/Library/Include/CrtLibSupport.h

@@ -133,6 +133,7 @@ void           *malloc     (size_t);
 void           *realloc    (void *, size_t);
 void           free        (void *);
 void           *memset     (void *, int, size_t);
+int            memcmp      (const void *, const void *, size_t);
 int            isdigit     (int);
 int            isspace     (int);
 int            isxdigit    (int);