Fixes to the libpayload build system

- its Makefile is part of the libpayload project
- fix conversion bug in powerpc's Makefile.inc

Change-Id: I84f2da092c3733ea7d0f232cb3768078cf13dfd5
Signed-off-by: Patrick Georgi <patrick@georgi-clan.de>
Reviewed-on: http://review.coreboot.org/79
Tested-by: build bot (Jenkins)
Reviewed-by: Uwe Hermann <uwe@hermann-uwe.de>
diff --git a/payloads/libpayload/Makefile b/payloads/libpayload/Makefile
index b976baa..667822d 100644
--- a/payloads/libpayload/Makefile
+++ b/payloads/libpayload/Makefile
@@ -1,5 +1,5 @@
 ##
-## This file is part of the coreboot project.
+## This file is part of the libpayload project.
 ##
 ## Copyright (C) 2008 Advanced Micro Devices, Inc.
 ## Copyright (C) 2008 Uwe Hermann <uwe@hermann-uwe.de>
diff --git a/payloads/libpayload/arch/powerpc/Makefile.inc b/payloads/libpayload/arch/powerpc/Makefile.inc
index bfbec27..44ce431 100644
--- a/payloads/libpayload/arch/powerpc/Makefile.inc
+++ b/payloads/libpayload/arch/powerpc/Makefile.inc
@@ -29,6 +29,6 @@
 
 head.o-y := head.S
 libc-y += main.c sysinfo.c
-libc-y += timer.c coreboot.c util.S.c
+libc-y += timer.c coreboot.c util.S
 libc-y += exec.S virtual.c