Fix lint test for build directories

config files are rename()d, which fails across filesystem borders.
So force temporary config files in current directory.

Change-Id: I583c2ab9a822a6f99f838778aa17ffd2d47eaed1
Signed-off-by: Patrick Georgi <patrick@georgi-clan.de>
Reviewed-on: http://review.coreboot.org/680
Tested-by: build bot (Jenkins)
Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>

util/lint/lint-002-build-dir-handling

@@ -47,7 +47,7 @@ if [ "$MAKE" = "" ]; then
 fi
 
 # prepare a config to use
-TMPCONFIG=`mktemp`
+TMPCONFIG=`mktemp .tmpconfig.XXXXXX`
 rm -f $TMPCONFIG
 $MAKE NOMKDIR=1 DOTCONFIG=$TMPCONFIG allyesconfig >/dev/null