ocfs2: remove kfree() redundant null checks

ocfs2: remove kfree() redundant null checks

smatch analysis indicates a number of redundant NULL checks before
calling kfree(), e.g.,

fs/ocfs2/alloc.c:6138 ocfs2_begin_truncate_log_recovery() info:
 redundant null check on *tl_copy calling kfree()

fs/ocfs2/alloc.c:6755 ocfs2_zero_range_for_truncate() info:
 redundant null check on pages calling kfree()

etc....

Signed-off-by: Tim Gardner <tim.gardner@canonical.com>
Cc: Mark Fasheh <mfasheh@suse.com>
Acked-by: Joel Becker <jlbec@evilplan.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>