Bluetooth: Mesh: Don't reset PB ADV reliable timer on retransmit

The send_reliable function was reused in multiple places as part of the
k_delayed_work changes for Bluetooth Mesh in #33782. This function
contains a line that resets the start timer, causing prov_retransmit to
continously move the goal post for when to give up sending.

Extract this line out of the send_reliable function, and put it along
with the other link.tx initialization in bearer_ctl_send and
prov_send_adv.

Signed-off-by: Trond Einar Snekvik <[email protected]>

subsys/bluetooth/mesh/pb_adv.c

@@ -560,8 +560,6 @@ static void send_reliable(void)
 {
  int i;
 
- link.tx.start = k_uptime_get();
-
  for (i = 0; i < ARRAY_SIZE(link.tx.buf); i++) {
  struct net_buf *buf = link.tx.buf[i];
 
@@ -642,6 +640,7 @@ static int bearer_ctl_send(uint8_t op, const void *data, uint8_t data_len,
  net_buf_add_mem(buf, data, data_len);
 
  if (reliable) {
+ link.tx.start = k_uptime_get();
  link.tx.buf[0] = buf;
  send_reliable();
  } else {
@@ -677,6 +676,7 @@ static int prov_send_adv(struct net_buf_simple *msg,
  link.tx.buf[0] = start;
  link.tx.cb = cb;
  link.tx.cb_data = cb_data;
+ link.tx.start = k_uptime_get();
 
  BT_DBG("xact_id: 0x%x len: %u", link.tx.id, msg->len);