transport: use a bitmask for the transport

Move the transport's names in a local array in the transport
framework.

Replace the string struct transport::name, that identifies the
transport, with a bitmask where each bit corresponds to one of the
available transports.

Change-Id: I6bdf7264d5979c355299f63fcf80bf54dcd95cee
Signed-off-by: Antonio Borneo <borneo.antonio@gmail.com>
Reviewed-on: https://review.openocd.org/c/openocd/+/8674
Tested-by: jenkins
Reviewed-by: zapb <dev@zapb.de>

src/jtag/swim.c

@@ -136,7 +136,7 @@ static int swim_transport_init(struct command_context *cmd_ctx)
 }
 
 static struct transport swim_transport = {
-	.name = "swim",
+	.id = TRANSPORT_SWIM,
 	.select = swim_transport_select,
 	.init = swim_transport_init,
 };