payloads: Add an option to compress secondary payloads

Both GRUB and SeaBIOS can chainload lzma compressed payloads.
Therefore it is beneficial to compress secondary payloads
like Memtest86+, coreinfo, nvramcui,... for both size reasons and
often also speed reasons since the limiting factor is generally the
IO of the boot device.

Tested with SeaBIOS and memtest86+ master on Thinkpad X220.

Change-Id: Iddfd6fcf4112d255cc7b2b49b99bf5ea4d6f8db4
Signed-off-by: Arthur Heymans <arthur@aheymans.xyz>
Reviewed-on: https://review.coreboot.org/23639
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Martin Roth <martinroth@google.com>

payloads/Kconfig

@@ -82,6 +82,13 @@ config PAYLOAD_IS_FLAT_BINARY
 	  Add the payload to cbfs as a flat binary type instead of as an
 	  elf payload
 
+config COMPRESS_SECONDARY_PAYLOAD
+	bool "Use LZMA compression for secondary payloads"
+	default y
+	help
+	  In order to reduce the size secondary payloads take up in the
+	  ROM chip they can be compressed using the LZMA algorithm.
+
 menu "Secondary Payloads"
 
 config COREINFO_SECONDARY_PAYLOAD