mb/starlabs/lite/glk: Disable PMC device

These boards use BootGuard, which isn't fully working in coreboot as
it requires the bootblock to be relocatable.

Turn off the PMC to workaround the missing BootGuard requirements, so
that they will turn on when pressing the power button.

Change-Id: Idd03684d9fb4573fc160e17ac2c28c39bc8b2ddd
Signed-off-by: Sean Rhodes <sean@starlabs.systems>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/86830
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Matt DeVillier <matt.devillier@gmail.com>

src/mainboard/starlabs/lite/variants/glk/devicetree.cb

@@ -65,7 +65,7 @@ chip soc/intel/apollolake
 				device generic 0 on end
 			end
 		end
-		device ref pmc		on  end
+		device ref pmc		off end
 		device ref p2sb		on  end
 		device ref fast_spi	on  end
 		device ref sram		on  end