jffs2: Avoid unneeded 'if' before kfree

kfree() deals gracefully with NULL pointers, so it's pointless to test for
one prior to calling it.
This removes such a test from jffs2_scan_medium().

Signed-off-by: Jesper Juhl <jj@chaosbits.net>
Signed-off-by: Artem Bityutskiy <dedekind1@gmail.com>

fs/jffs2/scan.c

@@ -275,9 +275,7 @@ int jffs2_scan_medium(struct jffs2_sb_info *c)
 	else
 		c->mtd->unpoint(c->mtd, 0, c->mtd->size);
 #endif
-	if (s)
 	kfree(s);
-
 	return ret;
 }