soc/intel/broadwell: Separate PCH in devicetree

Flesh out the PCH configuration into a separate chip. Keep it within the
Broadwell SoC directory for now, to ease moving files around. The boards
were prepared beforehand and the devicetrees require next to no changes.

Tested on out-of-tree Acer Aspire E5-573, still boots.

Change-Id: I28d948f3e6d85e669d12b29516d867c1d1ae9e1a
Signed-off-by: Angel Pons <th3fanbus@gmail.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/46700
Reviewed-by: Arthur Heymans <arthur@aheymans.xyz>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

src/mainboard/intel/wtm2/devicetree.cb

@@ -17,7 +17,7 @@ chip soc/intel/broadwell
 		device pci 02.0 on  end	# vga controller
 		device pci 03.0 on  end	# mini-hd audio
 
-#		chip soc/intel/broadwell/pch
+		chip soc/intel/broadwell/pch
 			register "alt_gp_smi_en" = "0x0000"
 			register "gpe0_en_1" = "0x00000400"
 			register "gpe0_en_2" = "0x00000000"
@@ -55,6 +55,6 @@ chip soc/intel/broadwell
 			device pci 1f.2 on  end	# SATA Controller
 			device pci 1f.3 on  end	# SMBus
 			device pci 1f.6 on  end	# Thermal
-#		end
+		end
 	end
 end