Disable CLKM in atspi-txrx, to reduce interferences.

- atrf/tools/atspi-txrx/atspi-txrx.c: disable CLKM when sending or receiving
- TODO: minor edit, missed in last commit

TODO

@@ -55,7 +55,7 @@ Things not done yet
 - verify that the Ben can output an a) 16 MHz clock, and b) with +/- 40 ppm
 
 - replace discrete balun and filter with integrated solution, to reduce BOM
-  size, maybe cost, insertion loss, and PCB space (see ECN0003)
+  size, maybe cost, insertion loss, and PCB space (see ATRF/ECN0003)
 
 - check if we really need three DC blocking caps in the RF path
 

atrf/tools/atspi-txrx/atspi-txrx.c

@@ -57,6 +57,7 @@ static usb_dev_handle *init_txrx(int trim)
 	atspi_reg_write(dev, REG_TRX_STATE, TRX_CMD_TRX_OFF);
 	atspi_reg_write(dev, REG_XOSC_CTRL,
 	    (XTAL_MODE_INT << XTAL_MODE_SHIFT) | trim);
+	atspi_reg_write(dev, REG_TRX_CTRL_0, 0); /* disable CLKM */
 
 	return dev;
 }