minixfs now uses kmap_local_page(), so we can't call kunmap() to
undo it.  This one call was missed as part of the commit this fixes.

Fixes: 6628f69e (minixfs: Use dir_put_page() in minix_unlink() and minix_rename())
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Link: https://lore.kernel.org/r/20240709195841.1986374-1-willy@infradead.orgSigned-off-by: Christian Brauner <brauner@kernel.org>