patch 8.2.0967: unnecessary type casts for vim_strnsave()

Problem:    Unnecessary type casts for vim_strnsave().
Solution:   Remove the type casts.
diff --git a/src/usercmd.c b/src/usercmd.c
index cdc46a1..de49d41 100644
--- a/src/usercmd.c
+++ b/src/usercmd.c
@@ -676,7 +676,7 @@
     }
 
     if (arg != NULL)
-	*compl_arg = vim_strnsave(arg, (int)arglen);
+	*compl_arg = vim_strnsave(arg, arglen);
 # endif
     return OK;
 }
@@ -939,7 +939,7 @@
     {
 	if (ga_grow(gap, 1) != OK)
 	    goto fail;
-	if ((p = vim_strnsave(name, (int)name_len)) == NULL)
+	if ((p = vim_strnsave(name, name_len)) == NULL)
 	    goto fail;
 
 	cmd = USER_CMD_GA(gap, i);