libpayload: Kconfig include in lpgcc

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>
diff --git a/payloads/libpayload/bin/lpgcc b/payloads/libpayload/bin/lpgcc
index 9346639..17d8eda 100755
--- a/payloads/libpayload/bin/lpgcc
+++ b/payloads/libpayload/bin/lpgcc
@@ -159,7 +159,7 @@
 trygccoption -fno-stack-protector
 [ $? -eq 0 ] && _CFLAGS="$_CFLAGS -fno-stack-protector"
 
-_CFLAGS="$_CFLAGS -I`$DEFAULT_CC $_ARCHEXTRA -print-search-dirs | head -n 1 | cut -d' ' -f2`include"
+_CFLAGS="$_CFLAGS -include $BASE/../include/kconfig.h -I`$DEFAULT_CC $_ARCHEXTRA -print-search-dirs | head -n 1 | cut -d' ' -f2`include"
 
 _LDFLAGS="-L$BASE/../lib -L$_LIBDIR $_LDSCRIPT -static"