patch 8.1.0927: USE_CR is never defined

Problem:    USE_CR is never defined.
Solution:   Remove usage of USE_CR. (Ken Takata, closes #3958)
diff --git a/src/evalfunc.c b/src/evalfunc.c
index e693ef9..f1cb9dc 100644
--- a/src/evalfunc.c
+++ b/src/evalfunc.c
@@ -13431,20 +13431,7 @@
     else
     {
 	res = get_cmd_output(tv_get_string(&argvars[0]), infile, flags, NULL);
-#ifdef USE_CR
-	/* translate <CR> into <NL> */
-	if (res != NULL)
-	{
-	    char_u	*s;
-
-	    for (s = res; *s; ++s)
-	    {
-		if (*s == CAR)
-		    *s = NL;
-	    }
-	}
-#else
-# ifdef USE_CRNL
+#ifdef USE_CRNL
 	/* translate <CR><NL> into <NL> */
 	if (res != NULL)
 	{
@@ -13459,7 +13446,6 @@
 	    }
 	    *d = NUL;
 	}
-# endif
 #endif
 	rettv->vval.v_string = res;
 	res = NULL;