nb/intel/haswell/finalize.c: Lock PCU DDR PTM

This register has a lock bit. The Haswell System Agent BIOS Spec
revision 0.6.0 indicates it needs to be set, thus set it. Note that
Broadwell already locks this register.

Tested on Asrock B85M Pro4, still boots and register is locked.

Change-Id: Ie23b825e708edbfc04ec0d7783f868e8632eb608
Signed-off-by: Angel Pons <th3fanbus@gmail.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/46679
Reviewed-by: Nico Huber <nico.h@gmx.de>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
diff --git a/src/northbridge/intel/haswell/registers/mchbar.h b/src/northbridge/intel/haswell/registers/mchbar.h
index 96d08bf..bd99cee 100644
--- a/src/northbridge/intel/haswell/registers/mchbar.h
+++ b/src/northbridge/intel/haswell/registers/mchbar.h
@@ -24,6 +24,8 @@
 /* PAVP message register. Bit 0 locks PAVP settings, and bits [31..20] are an offset. */
 #define MMIO_PAVP_MSG		0x5500
 
+#define PCU_DDR_PTM_CTL		0x5880
+
 /* Some power MSRs are also represented in MCHBAR */
 #define MCH_PKG_POWER_LIMIT_LO	0x59a0
 #define MCH_PKG_POWER_LIMIT_HI	0x59a4