arch/x86: Remove RELOCATABLE_RAMSTAGE

We always have it, no need to support opting-out.

For PLATFORM_HAS_DRAM_CLEAR there is a dependency of ramstage
located inside CBMEM, which is only true with ARCH_X86.

Change-Id: I5cbf4063c69571db92de2d321c14d30c272e8098
Signed-off-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/43014
Reviewed-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-by: Nico Huber <nico.h@gmx.de>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

src/security/memory/Kconfig

@@ -4,9 +4,8 @@ menu "Memory initialization"
 
 config PLATFORM_HAS_DRAM_CLEAR
 	bool
-	default y if ARCH_X86
-	default n
-	depends on RELOCATABLE_RAMSTAGE
+	default y
+	depends on ARCH_X86
 	help
 	  Selected by platforms that support clearing all DRAM
 	  after DRAM initialization.

src/security/memory/memory_clear.c

@@ -77,8 +77,7 @@ static void clear_memory(void *unused)
 	void *baseptr = NULL;
 	size_t size = 0;
 
-	/* Only skip CBMEM, as RELOCATABLE_RAMSTAGE is a requirement, no need
-	 * to separately protect stack or heap */
+	/* Only skip CBMEM, stage program, stack and heap are included there. */
 
 	cbmem_get_region(&baseptr, &size);
 	memranges_insert(&mem, (uintptr_t)baseptr, size, BM_MEM_TABLE);