nb/intel/pineview: Use MTRR as a proxy for proper reset

On reset this platform can sometimes hang.
This also fixes pineview mainboards not building due to the symbol
'check_mtrr' lacking.

Change-Id: I61fe77113004ea664522bda549240a33e3742a98
Signed-off-by: Arthur Heymans <arthur@aheymans.xyz>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/33010
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Angel Pons <th3fanbus@gmail.com>
Reviewed-by: HAOUAS Elyes <ehaouas@noos.fr>

src/northbridge/intel/pineview/Makefile.inc

@@ -16,6 +16,7 @@
 
 ifeq ($(CONFIG_NORTHBRIDGE_INTEL_PINEVIEW),y)
 
+bootblock-y += ../../../cpu/x86/early_reset.S
 bootblock-y += bootblock.c
 
 ramstage-y += ram_calc.c