core: use larger buffer for string in commit_port_options()

Use sizeof(queue_id_str), so we don't rely on _MAX_QUEUE_ID_STR_LEN
being the correct size for the string.

Also, let's create an excessively large buffer. True, the previous size
should have always be enough, so in practice there is no difference.

But what if it were not? Should we try to handle an error? How? Just asserting
or report a failure? But we don't because the error cannot happen, can't
it?
Don't answer any of these questions, but by making the string buffer
larger, it's even less likely that these questions become relevant.
If for some reason nm_device_get_iface() gives a long string, then we
don't care and let kernel reject the invalid interface name.

src/core/devices/nm-device-bond.c

@@ -407,16 +407,10 @@ act_stage1_prepare(NMDevice *device, NMDeviceStateReason *out_failure_reason)
     return ret;
 }
 
-/*
- * The queue id format is '$interface_name:$queue_id'
- * The max queue 65535 hold 5 chars.
- */
-#define _MAX_QUEUE_ID_STR_LEN 5 + IFNAMSIZ + 1 + 1
-
 static void
 commit_port_options(NMDevice *bond_device, NMDevice *port, NMSettingBondPort *set_port)
 {
-    char queue_id_str[_MAX_QUEUE_ID_STR_LEN];
+    char queue_id_str[IFNAMSIZ + NM_STRLEN(":") + 5 + 100];
 
     /*
      * The queue-id of bond port is read only, we should modify bond interface using:
@@ -424,7 +418,7 @@ commit_port_options(NMDevice *bond_device, NMDevice *port, NMSettingBondPort *se
      * Kernel allows parital editing, so no need to care about other bond ports.
      */
     g_snprintf(queue_id_str,
-               _MAX_QUEUE_ID_STR_LEN,
+               sizeof(queue_id_str),
                "%s:%" G_GUINT32_FORMAT,
                nm_device_get_iface(port),
                set_port ? nm_setting_bond_port_get_queue_id(set_port) : NM_BOND_PORT_QUEUE_ID_DEF);