AP_HAL_Linux: move check for _split_transfers

This is likely not true, so allow not to check the other conditions.
Also remove comment since this is going to be added to the method.

libraries/AP_HAL_Linux/I2CDevice.cpp

@@ -154,12 +154,7 @@ I2CDevice::~I2CDevice()
 bool I2CDevice::transfer(const uint8_t *send, uint32_t send_len,
                          uint8_t *recv, uint32_t recv_len)
 {
-    if (send_len > 0 && recv_len > 0 && _split_transfers) {
-        /*
-          optionally split all I2C transfers. This is needed for some
-          devices (such as LidarLite) that require that STOP only
-          happen with SCL high
-         */
+    if (_split_transfers && send_len > 0 && recv_len > 0) {
         return transfer(send, send_len, nullptr, 0) &&
             transfer(nullptr, 0, recv, recv_len);
     }