AP_Airspeed: use take_blocking instead of HAL_SEMAPHORE_BLOCK_FOREVER

this makes for cleaner and smaller code as the failure case is not
needed

libraries/AP_Airspeed/AP_Airspeed_MS5525.cpp

@@ -71,9 +71,7 @@ bool AP_Airspeed_MS5525::init()
         if (!dev) {
             continue;
         }
-        if (!dev->get_semaphore()->take(HAL_SEMAPHORE_BLOCK_FOREVER)) {
-            continue;
-        }
+        dev->get_semaphore()->take_blocking();
 
         // lots of retries during probe
         dev->set_retries(5);

libraries/AP_Airspeed/AP_Airspeed_SDP3X.cpp

@@ -68,9 +68,7 @@ bool AP_Airspeed_SDP3X::init()
         if (!_dev) {
             continue;
         }
-        if (!_dev->get_semaphore()->take(HAL_SEMAPHORE_BLOCK_FOREVER)) {
-            continue;
-        }
+        _dev->get_semaphore()->take_blocking();
 
         // lots of retries during probe
         _dev->set_retries(10);
@@ -84,9 +82,7 @@ bool AP_Airspeed_SDP3X::init()
         // these delays are needed for reliable operation
         _dev->get_semaphore()->give();
         hal.scheduler->delay_microseconds(20000);
-        if (!_dev->get_semaphore()->take(HAL_SEMAPHORE_BLOCK_FOREVER)) {
-            continue;
-        }
+        _dev->get_semaphore()->take_blocking();
 
         // start continuous average mode
         if (!_send_command(SDP3X_CONT_MEAS_AVG_MODE)) {
@@ -97,9 +93,7 @@ bool AP_Airspeed_SDP3X::init()
         // these delays are needed for reliable operation
         _dev->get_semaphore()->give();
         hal.scheduler->delay_microseconds(20000);
-        if (!_dev->get_semaphore()->take(HAL_SEMAPHORE_BLOCK_FOREVER)) {
-            continue;
-        }
+        _dev->get_semaphore()->take_blocking();
 
         // step 3 - get scale
         uint8_t val[9];