arch/x86: Obsolete CACHE_AS_RAM config

It was originally inverse of romcc-built romstages on x86,
and is currently always true on x86.

Change-Id: I65fa6b3ce8a86781724bbf08f5eadee4112667c4
Signed-off-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/34806
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Aaron Durbin <adurbin@chromium.org>

src/include/symbols.h

@@ -72,7 +72,7 @@ DECLARE_REGION(bl31)
  * (Does not necessarily mean that the memory is accessible.) */
 static inline int preram_symbols_available(void)
 {
-	return !CONFIG(CACHE_AS_RAM) || ENV_CACHE_AS_RAM;
+	return !CONFIG(ARCH_X86) || ENV_CACHE_AS_RAM;
 }
 
 #endif /* __SYMBOLS_H */