hfsplus: avoid double unload_nls() on mount failure

hfsplus: avoid double unload_nls() on mount failure

The recent commit "hfsplus: ensure sb->s_fs_info is always cleaned up"
[1] introduced a custom ->kill_sb() handler (hfsplus_kill_super) that
cleans up the s_fs_info structure (including the NLS table) on
superblock destruction.

However, the error handling path in hfsplus_fill_super() still calls
unload_nls() before returning an error. Since the VFS layer calls
->kill_sb() when fill_super fails, this results in unload_nls() being
called twice for the same sbi->nls pointer: once in hfsplus_fill_super()
and again in hfsplus_kill_super() (via delayed_free).

Remove the explicit unload_nls() call from the error path in
hfsplus_fill_super() to rely solely on the cleanup in ->kill_sb().

[1] https://lore.kernel.org/r/20251201222843.82310-3-mehdi.benhadjkhelifa@gmail.com/

Reported-by: Al Viro <viro@zeniv.linux.org.uk>
Link: https://lore.kernel.org/r/20260203043806.GF3183987@ZenIV/
Signed-off-by: Shardul Bankar <shardul.b@mpiricsoftware.com>
Link: https://lore.kernel.org/r/20260204170440.1337261-1-shardul.b@mpiricsoftware.com
Signed-off-by: Viacheslav Dubeyko <slava@dubeyko.com>