ext4: remove unneeded forward declaration in namei.c

Remove unneeded forward declaration in namei.c

Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com>
Reviewed-by: Ojaswin Mujoo <ojaswin@linux.ibm.com>
Reviewed-by: Zhang Yi <yi.zhang@huawei.com>
Link: https://patch.msgid.link/20250123162050.2114499-3-shikemeng@huaweicloud.com


Signed-off-by: Theodore Ts'o <tytso@mit.edu>