soc/intel/baytrail: Add native refcode replacement

- This is a reverse engineered re-implementation of refcode.elf on
	Bay Trail
- Tested on GBYT4, should work everywhere as it's meant to behave
	exactly the same as the binary refcode

Signed-off-by: Mate Kukri <kukri.mate@gmail.com>
Change-Id: I91977c509022b0078804dc151d27296260e24bc4
Reviewed-on: https://review.coreboot.org/c/coreboot/+/43133
Reviewed-by: Arthur Heymans <arthur@aheymans.xyz>
Reviewed-by: Angel Pons <th3fanbus@gmail.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
diff --git a/src/soc/intel/baytrail/Kconfig b/src/soc/intel/baytrail/Kconfig
index a436e24..b23f56d 100644
--- a/src/soc/intel/baytrail/Kconfig
+++ b/src/soc/intel/baytrail/Kconfig
@@ -133,13 +133,15 @@
 
 config HAVE_REFCODE_BLOB
 	depends on ARCH_X86
-	bool "An external reference code blob should be put into cbfs."
+	bool "Use a binary refcode blob instead of native ModPHY init"
 	default n
 	help
-	 The reference code blob will be placed into cbfs.
+	 Use the ChromeBook refcode to intitialize high-speed PHYs instead of
+	 native code.
 
 if HAVE_REFCODE_BLOB
 
+# Ask for the blob if the user wants it
 config REFCODE_BLOB_FILE
 	string "Path and filename to reference code blob."
 	default "refcode.elf"