soc/intel/{skl,kbl}: ensure C1E is disabled after S3 resume

C1E is disabled by the kernel driver intel_idle at boot.  This does not
address the S3 resume case, so we lose state and C1E is enabled after S3
resume.

Disable C1E for SKL and KBL.  This gives a coherent state before
and after S3 resume.

TEST='iotools rdmsr cpu 0x1fc'. Returns the same value after boot and S3
resume with bit [1] set to zero (0x20005d).

Change-Id: I1343f343bfac9b787f13c15b812c0a201dcccb38
Signed-off-by: Cole Nelson <colex.nelson@intel.com>
Reviewed-on: https://review.coreboot.org/27125
Reviewed-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-by: Furquan Shaikh <furquan@google.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

src/soc/intel/skylake/cpu.c

@@ -310,9 +310,9 @@ static void configure_misc(void)
 	msr.hi = 0;
 	wrmsr(IA32_PACKAGE_THERM_INTERRUPT, msr);
 
-	/* Enable PROCHOT */
 	msr = rdmsr(MSR_POWER_CTL);
 	msr.lo |= (1 << 0);	/* Enable Bi-directional PROCHOT as an input*/
+	msr.lo &= ~POWER_CTL_C1E_MASK;	/* Disable C1E */
 	msr.lo |= (1 << 23);	/* Lock it */
 	wrmsr(MSR_POWER_CTL, msr);
 }