atm: iphase: return -ENOMEM instead of -1 in case of failed kmalloc()

Smatch complains about returning hard coded error codes, silence this
warning.

drivers/atm/iphase.c:115 ia_enque_rtn_q() warn: returning -1 instead of -ENOMEM is sloppy
Signed-off-by: NTillmann Heidsieck <theidsieck@leenox.de>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/atm/iphase.c

@@ -112,7 +112,8 @@ static void ia_enque_head_rtn_q (IARTN_Q *que, IARTN_Q * data)
 
 static int ia_enque_rtn_q (IARTN_Q *que, struct desc_tbl_t data) {
    IARTN_Q *entry = kmalloc(sizeof(*entry), GFP_ATOMIC);
-   if (!entry) return -1;
+   if (!entry)
+      return -ENOMEM;
    entry->data = data;
    entry->next = NULL;
    if (que->next == NULL)