gitignore: remove stale /LOG pattern

The /LOG directory was created by the old MAKEALL tool, which was
deleted by commit c8a3777c51b9 ("Drop the MAKEALL tool").

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
diff --git a/.gitignore b/.gitignore
index 860b179..9110eda 100644
--- a/.gitignore
+++ b/.gitignore
@@ -48,7 +48,6 @@
 #
 # Generated files
 #
-/LOG
 /spl/
 /tpl/
 /defconfig