ms: init blade with fpga control

Blade 1 defaults to fpga tuning, but the blade 2 code defaults to host,
which does 8000 register reads and writes. The only way to speed this up
is to set the env var, which reduces opening the blade device from 10 to
1 seconds.

Change-Id: I32fe31f1e11f4ceb3c864ec8739d177e780d0a7e

Transceiver52M/ms/bladerf_specific.h

@@ -254,6 +254,8 @@ struct blade_hw {
 
 		bladerf_log_set_verbosity(BLADERF_LOG_LEVEL_DEBUG);
 		bladerf_set_usb_reset_on_open(true);
+
+		setenv("BLADERF_DEFAULT_TUNING_MODE","fpga",1); // ensure blade 2 does not spend 10 seconds initializing host control
 		blade_check(bladerf_open, &dev, "");
 		if (!dev) {
 			std::cerr << "open failed, device missing?" << std::endl;