Strip quotes from $(objcbfs)

Otherwise object paths will look like build/cbfs/"fallback"/...

Change-Id: I3e60f90f7490e71b0da075d3ea8fc847abc07938
Signed-off-by: Stefan Reinauer <reinauer@google.com>
Reviewed-on: http://review.coreboot.org/1700
Reviewed-by: Marc Jones <marcj303@gmail.com>
Tested-by: build bot (Jenkins)
diff --git a/Makefile.inc b/Makefile.inc
index 7d32a96..e499bac 100644
--- a/Makefile.inc
+++ b/Makefile.inc
@@ -30,7 +30,7 @@
 ## Final build results, which CBFSTOOL uses to create the final
 ## rom image file, are placed under $(objcbfs).
 ## These typically have suffixes .debug .elf .bin and .map
-export objcbfs := $(obj)/cbfs/$(CONFIG_CBFS_PREFIX)
+export objcbfs := $(obj)/cbfs/$(call strip_quotes,$(CONFIG_CBFS_PREFIX))
 
 ## Based on the active configuration, Makefile conditionally collects
 ## the required assembly includes and saves them in a file.