nb/intel/sandybridge: Drop spurious register write

It does not make sense to disable an optimization that was not enabled
before, especially if that optimization only applies to Ivy Bridge.

Tested, still boots and can suspend correctly with:
- Asus P8Z77-V LX2      with i5-3330 and Windows 10
- Gigabyte GA-H61MA-D3V with i5-2400 and Arch Linux

Change-Id: I9f3eb545585824bbdf51e33f0592e7daa1c425af
Signed-off-by: Angel Pons <th3fanbus@gmail.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/39623
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Matt DeVillier <matt.devillier@gmail.com>
Reviewed-by: Nico Huber <nico.h@gmx.de>

src/northbridge/intel/sandybridge/raminit_common.c

@@ -3236,11 +3236,4 @@ void restore_timings(ramctr_timing *ctrl)
 		MCHBAR32_AND(GDCRCMDDEBUGMUXCFG_Cz_S(channel), ~0x3f000000);
 		udelay(2);
 	}
-
-	/*
-	 * Disable IOSAV_n_SPECIAL_COMMAND_ADDR optimization.
-	 * FIXME: This must only be done on Ivy Bridge. Moreover, this instance seems to be
-	 *        spurious, because nothing else enabled this optimization before.
-	 */
-	MCHBAR32(MCMNTS_SPARE) = 0;
 }