scripts: objdiff: change the extension of disassembly from .o to .dis

Prior to this commit, the command "scripts/objdiff record path/to/*.o"
disassembled the given object into ".tmp_objdiff/path/to/*.o" file.

The problem here is that recorded disassemblies are lost if we run
"make clean" because it removes all the *.o files.
Disassembled code should be dumped into *.dis instead of *.o files.
Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
Acked-by: Jason Cooper <jason@lakedaemon.net>
Signed-off-by: Michal Marek <mmarek@suse.cz>

scripts/objdiff

@@ -65,13 +65,14 @@ dorecord() {
 
 	for f in $FILES; do
 		dir=$(get_output_dir $f)
-		bn="${f##*/}"
+		base=${f##*/}
+		dis=$dir/${base%.o}.dis
 
 		[ ! -d "$dir" ] && mkdir -p $dir
 
 		# remove addresses for a more clear diff
 		# http://dummdida.tumblr.com/post/60924060451/binary-diff-between-libc-from-scientificlinux-and
-		$OBJDUMP -D $f | sed "s/^[[:space:]]\+[0-9a-f]\+//" > $dir/$bn
+		$OBJDUMP -D $f | sed "s/^[[:space:]]\+[0-9a-f]\+//" > $dis
 	done
 }