X60: trigger save cmos on volume/brightness change

Change-Id: I020e06bc311c4e4327c9d3cf2c379dc8fe070a7a
Signed-off-by: Sven Schnelle <svens@stackframe.org>
Reviewed-on: http://review.coreboot.org/25
Tested-by: build bot (Jenkins)
Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>

src/mainboard/lenovo/x60/cmos.layout

@@ -108,6 +108,7 @@ entries
 1052         4       r       0        C1DRT1
 
 1064         8       h       0        volume
+1072         8       h       0        tft_brightness
 # -----------------------------------------------------------------
 
 enumerations