Mares: improve BT discovery logic

At least in one of the logs we saw there seemed to be trailing spaces.
It should be enough for the BT name to start with "Mares Genius" in
order to be recognized.

Suggested-by: Jef Driesen <jef@libdivecomputer.org>
Signed-off-by: Dirk Hohndel <dirk@hohndel.org>

core/btdiscovery.cpp

@@ -77,7 +77,7 @@ static dc_descriptor_t *getDeviceType(QString btName)
 		// so let's just randomly pick one
 		product = "Quad";
 		// Some we can pick out directly
-		if (btName == "Mares Genius")
+		if (btName.startsWith("Mares Genius"))
 			product = "Genius";
 	}