src/soc/intel: skl,cnl,icl: remove unneeded check in cbmem_top()

As stated in CB:36334 cbmem_top() should not be called before memory is
initialized. Therefore drop the check to see if MRC finished.

Change-Id: I964a20a5e9aa69fdb75413c36a17d34b7ba00098
Signed-off-by: Michael Niewöhner <foss@mniewoehner.de>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/36386
Reviewed-by: Arthur Heymans <arthur@aheymans.xyz>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

src/soc/intel/cannonlake/memmap.c

@@ -257,15 +257,6 @@ void *cbmem_top(void)
 {
 	struct ebda_config ebda_cfg;
 
-	/*
-	 * Check if Tseg has been initialized, we will use this as a flag
-	 * to check if the MRC is done, and only then continue to read the
-	 * PRMMR_BASE MSR. The system hangs if PRMRR_BASE MSR is read before
-	 * PRMRR_MASK MSR lock bit is set.
-	 */
-	if (sa_get_tseg_base() == 0)
-		return NULL;
-
 	retrieve_ebda_object(&ebda_cfg);
 
 	return (void *)(uintptr_t)ebda_cfg.tolum_base;

src/soc/intel/icelake/memmap.c

@@ -236,15 +236,6 @@ void *cbmem_top(void)
 {
 	struct ebda_config ebda_cfg;
 
-	/*
-	 * Check if Tseg has been initialized, we will use this as a flag
-	 * to check if the MRC is done, and only then continue to read the
-	 * PRMMR_BASE MSR. The system hangs if PRMRR_BASE MSR is read before
-	 * PRMRR_MASK MSR lock bit is set.
-	 */
-	if (sa_get_tseg_base() == 0)
-		return NULL;
-
 	retrieve_ebda_object(&ebda_cfg);
 
 	return (void *)(uintptr_t)ebda_cfg.tolum_base;

src/soc/intel/skylake/memmap.c

@@ -258,15 +258,6 @@ void *cbmem_top(void)
 {
 	struct ebda_config ebda_cfg;
 
-	/*
-	 * Check if Tseg has been initialized, we will use this as a flag
-	 * to check if the MRC is done, and only then continue to read the
-	 * PRMMR_BASE MSR. The system hangs if PRMRR_BASE MSR is read before
-	 * PRMRR_MASK MSR lock bit is set.
-	 */
-	if (sa_get_tseg_base() == 0)
-		return NULL;
-
 	retrieve_ebda_object(&ebda_cfg);
 
 	return (void *)(uintptr_t)ebda_cfg.tolum_base;