lenovo/x60: use correct BLC_PWM_CTL value

Bit 16 in BLC_PWM_CTL enables brightness controls, but the
current value is generic. Use the proper value, obtained
by reading BLC_PWM_CTL while running the VBIOS.

Change-Id: Ib273359e1c285b405a9bb26fc217c2f7e255b99f
Signed-off-by: Francis Rowe <info@gluglug.org.uk>
Reviewed-on: https://review.coreboot.org/10624
Tested-by: build bot (Jenkins)
Reviewed-by: Nico Huber <nico.h@gmx.de>
1 file changed