BTA_HfClientEnable() function

* External Function Declarations * Function BTA_HfClientEnable * Description Enable the HF CLient service. When the enable * operation is complete the callback function will be * called with a BTA_HF_CLIENT_ENABLE_EVT. This function must * be called before other function in the HF CLient API are * called. * Returns BTA_SUCCESS if OK, BTA_FAILURE otherwise.