Move out some hardcoded strings in coreinfo to become Kconfig variables.

Move out some hardcoded strings in coreinfo to become Kconfig variables.
This is useful for use with (e.g.) Bayou in order let the user customize the
payload name, description, version, etc.

For instance, instead of using stock coreinfo and calling the payload
"coreinfo" and the Bayou menu item "Show system information" a user might
only be interested in an NVRAM dump payload. Thus, he/she can enable
only the NVRAM coreinfo module via Kconfig, and tell Kconfig to call
the payload "NVRAMdumper" and the Bayou menu item "Show NVRAM contents".

This is build-tested, and tested against Bayou in QEMU.

Signed-off-by: Uwe Hermann <uwe@hermann-uwe.de>
Acked-by: Jordan Crouse <jordan.crouse@amd.com>
git-svn-id: svn://svn.coreboot.org/coreboot/trunk@3472 2b7e53f0-3cfb-0310-b3e9-8179ed1497e1