patch 8.1.0810: too many #ifdefs

Problem:    Too many #ifdefs.
Solution:   Graduate FEAT_MBYTE, part 4.
diff --git a/src/if_py_both.h b/src/if_py_both.h
index 233489e..f15bdc3 100644
--- a/src/if_py_both.h
+++ b/src/if_py_both.h
@@ -24,11 +24,7 @@
 typedef int Py_ssize_t;  /* Python 2.4 and earlier don't have this type. */
 #endif
 
-#ifdef FEAT_MBYTE
-# define ENC_OPT ((char *)p_enc)
-#else
-# define ENC_OPT "latin1"
-#endif
+#define ENC_OPT ((char *)p_enc)
 #define DOPY_FUNC "_vim_pydo"
 
 static const char *vim_special_path = "_vim_path_";
@@ -985,11 +981,7 @@
     if (!(str = StringToChars(string, &todecref)))
 	return NULL;
 
-#ifdef FEAT_MBYTE
     len = mb_string2cells(str, (int)STRLEN(str));
-#else
-    len = STRLEN(str);
-#endif
 
     Py_XDECREF(todecref);