stdio: simplify __fremovelock()

... by removing extraneous NULL check, as free() already does it.

Signed-off-by: André Goddard Rosa <andre.goddard@gmail.com>
Change-Id: I0445f35c7ad0a049a0e4aee1fbe002ed2f13b94b
diff --git a/libc/stdio/flockfile.c b/libc/stdio/flockfile.c
index a81879e..bfb081c 100644
--- a/libc/stdio/flockfile.c
+++ b/libc/stdio/flockfile.c
@@ -205,8 +205,6 @@
             lock->file = NULL;
         }
         lock_table_unlock(t);
-
-        if (lock != NULL)
-            free(lock);
+        free(lock);
     }
 }