haswell: Move some MRC settings to devicetree

There's no generic way to tell whether a mainboard has an EC or not.
Making Kconfig symbols for these options seems overkill, too. So, just
put them on the devicetree. Also, drop unnecessary assignments when the
board's current value is zero, as the struct defaults to zero already.

Change-Id: If2ebac5fcab278c97dfaf8adc9d1e125888acafe
Signed-off-by: Angel Pons <th3fanbus@gmail.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/43129
Reviewed-by: Nico Huber <nico.h@gmx.de>
Reviewed-by: Tristan Corrick <tristan@corrick.kiwi>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
diff --git a/src/mainboard/lenovo/t440p/devicetree.cb b/src/mainboard/lenovo/t440p/devicetree.cb
index e18f72b..58f0ca8 100644
--- a/src/mainboard/lenovo/t440p/devicetree.cb
+++ b/src/mainboard/lenovo/t440p/devicetree.cb
@@ -11,6 +11,7 @@
 	register "gpu_panel_power_down_delay" = "500"
 	register "gpu_panel_power_up_delay" = "2000"
 	register "gpu_pch_backlight_pwm_hz" = "220"
+	register "ec_present" = "true"
 	device cpu_cluster 0x0 on
 		chip cpu/intel/haswell
 			register "c1_acpower" = "1"