Payloads will include headers from libpayload, which depend on kconfig.h, so it
has to be included in the command line produced by lpgcc.
Change-Id: I3b55928babba2896a112f8c5fae46365cf71d308
Signed-off-by: Paul Kocialkowski <contact@paulk.fr>
Reviewed-on: http://review.coreboot.org/11114
Tested-by: build bot (Jenkins)
Reviewed-by: Patrick Georgi <pgeorgi@google.com>