Fix issue where adv_handle of incorrect instance was modified

Fix issue where adv_handle of incorrect instance was modified

Reproduction steps:
1) bt_adapter_le_create_advertiser()     // ADV 1 create
2) bt_adapter_le_start_advertising_new() // ADV 1 start
3) bt_adapter_le_create_advertiser()     // ADV 2 create
4) bt_adapter_le_start_advertising_new() // ADV 2 start
5) register GATT Service                 // register gatt service
6) bt_gatt_server_start()                // GATT Server Start
7) bt_adapter_le_stop_advertising()      // ADV 1 stop
8) bt_adapter_le_destroy_advertiser()    // ADV 1 destroy --> RESOURCE_BUSY

Change-Id: I3ce3847b4a4acb478869c66fda8ce55e0dcdf212
Signed-off-by: Wootak Jung <wootak.jung@samsung.com>