mb/system76/lemp9: update power limits

Tested on lemp9, power limits are adjusted from the previously low
values to the values the thermal system can handle. This was
determined by increasing the values and running the system at 100%
CPU utilization until thermal throttling occured and the chassis
temperature became uncomfortable.

Signed-off-by: Jeremy Soller <jeremy@system76.com>
Change-Id: I5e176e9d98376f8e2dc415e4397efc456869e72d
Reviewed-on: https://review.coreboot.org/c/coreboot/+/43624
Reviewed-by: Michael Niewöhner <foss@mniewoehner.de>
Reviewed-by: Angel Pons <th3fanbus@gmail.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

src/mainboard/system76/lemp9/devicetree.cb

@@ -25,8 +25,8 @@ chip soc/intel/cannonlake
 # CPU (soc/intel/cannonlake/cpu.c)
 	# Power limit
 	register "power_limits_config" = "{
-		.tdp_pl1_override = 15,
-		.tdp_pl2_override = 25,
+		.tdp_pl1_override = 20,
+		.tdp_pl2_override = 30,
 	}"
 
 	# Enable "Intel Speed Shift Technology"