Kconfig: Allow x86 to compress pre-ram stages if not run XIP

On the intel/glkrvp
compressed:
- romstage: 29659
- verstage: 31303
non compressed:
- romstage: 46244
- verstage: 47012

On qemu (with some additional patch to not run XIP)
compressed:
- romstage: 11203
non compressed:
- romstage: 13924

Even with a small romstage the size improvements are substantial,
which should result in a speedup when loading the stage. On the
up/squared loading romstage is sped up by 9ms.

TESTED: successfully boot the up/squared & google/vilboz.

Change-Id: I6906c8b6df45f2433d92d2ff1d1748cc4926c73a
Signed-off-by: Arthur Heymans <arthur@aheymans.xyz>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/67749
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Sean Rhodes <sean@starlabs.systems>

src/Kconfig

@@ -179,14 +179,14 @@ config COMPRESS_RAMSTAGE
 
 config COMPRESS_PRERAM_STAGES
 	bool "Compress romstage and verstage with LZ4"
-	depends on !ARCH_X86 && (HAVE_ROMSTAGE || HAVE_VERSTAGE)
+	depends on (HAVE_ROMSTAGE || HAVE_VERSTAGE) && NO_XIP_EARLY_STAGES
 	# Default value set at the end of the file
 	help
 	  Compress romstage and (if it exists) verstage with LZ4 to save flash
 	  space and speed up boot, since the time for reading the image from SPI
 	  (and in the vboot case verifying it) is usually much greater than the
-	  time spent decompressing. Doesn't work for XIP stages (assume all
-	  ARCH_X86 for now) for obvious reasons.
+	  time spent decompressing. Doesn't work for XIP stages for obvious
+	  reasons.
 
 config COMPRESS_BOOTBLOCK
 	bool
@@ -1376,7 +1376,7 @@ config COMPRESS_RAMSTAGE
 	default y if !UNCOMPRESSED_RAMSTAGE
 
 config COMPRESS_PRERAM_STAGES
-	depends on !ARCH_X86
+	depends on (HAVE_ROMSTAGE || HAVE_VERSTAGE) && NO_XIP_EARLY_STAGES
 	default y
 
 config INCLUDE_CONFIG_FILE