CryptoPkg: Fix strncpy for BaseCryptLibMbedTls

REF: https://bugzilla.tianocore.org/show_bug.cgi?id=2817

Because the change for strncpy, add the strncpy implementation.

Signed-off-by: Wenxing Hou <wenxing.hou@intel.com>

CryptoPkg/Library/BaseCryptLibMbedTls/SysCall/DummyOpensslSupport.c

@@ -258,9 +258,28 @@ strcpy (
   const char  *strSource
   )
 {
-  // AsciiStrCpyS (strDest, MAX_STRING_SIZE, strSource);
+  AsciiStrCpyS (strDest, AsciiStrnSizeS (strSource, MAX_STRING_SIZE - 1), strSource);
-  // return strDest;
+  return strDest;
-  return NULL;
+}
+
+char *
+strncpy (
+  char        *strDest,
+  const char  *strSource,
+  size_t      count
+  )
+{
+  UINTN  DestMax = MAX_STRING_SIZE;
+
+  if (count < MAX_STRING_SIZE) {
+    DestMax = count + 1;
+  } else {
+    count = MAX_STRING_SIZE-1;
+  }
+
+  AsciiStrnCpyS (strDest, DestMax, strSource, (UINTN)count);
+
+  return strDest;
 }
 
 //