nimble/ll: Remove confusing symbol

BLE_PHY_TRANSITION is already used for transitions between TX/RX so this
name is confusing. And we actually do not need a special symbol here
since we can just use 0 - PHYs are numbered starting from 1.

Author: andrzej-kaczmarek

nimble/controller/include/controller/ble_ll_conn.h

@@ -173,8 +173,6 @@ struct ble_ll_conn_phy_data
 #define CONN_CUR_TX_PHY_MASK(csm)   (1 << ((csm)->phy_data.cur_tx_phy - 1))
 #define CONN_CUR_RX_PHY_MASK(csm)   (1 << ((csm)->phy_data.cur_rx_phy - 1))
 
-#define BLE_PHY_TRANSITION_INVALID    (0xFF)
-
 struct hci_conn_update
 {
     uint16_t handle;

nimble/controller/src/ble_ll_conn.c

@@ -754,7 +754,7 @@ ble_ll_conn_adjust_pyld_len(struct ble_ll_conn_sm *connsm, uint16_t pyld_len)
 #if (BLE_LL_BT5_PHY_SUPPORTED == 1)
     uint8_t phy_mode;
 
-    if (connsm->phy_tx_transition != BLE_PHY_TRANSITION_INVALID) {
+    if (connsm->phy_tx_transition) {
         phy_mode = ble_ll_phy_to_phy_mode(connsm->phy_tx_transition,
                                           connsm->phy_data.phy_options);
     } else {
@@ -1677,7 +1677,7 @@ ble_ll_conn_sm_new(struct ble_ll_conn_sm *connsm)
     connsm->phy_data.host_pref_tx_phys_mask = g_ble_ll_data.ll_pref_tx_phys;
     connsm->phy_data.host_pref_rx_phys_mask = g_ble_ll_data.ll_pref_rx_phys;
     connsm->phy_data.phy_options = 0;
-    connsm->phy_tx_transition = BLE_PHY_TRANSITION_INVALID;
+    connsm->phy_tx_transition = 0;
 #endif
 
     /* Reset current control procedure */

nimble/controller/src/ble_ll_ctrl.c

@@ -557,7 +557,7 @@ ble_ll_ctrl_phy_update_proc_complete(struct ble_ll_conn_sm *connsm)
     chk_proc_stop = 1;
     chk_host_phy = 1;
 
-    connsm->phy_tx_transition = BLE_PHY_TRANSITION_INVALID;
+    connsm->phy_tx_transition = 0;
 
     if (CONN_F_PEER_PHY_UPDATE(connsm)) {
         CONN_F_PEER_PHY_UPDATE(connsm) = 0;