hfs: make splice write available again

Since 5.10, splice() or sendfile() return EINVAL. This was
caused by commit 36e2c74 ("fs: don't allow splice read/write
without explicit ops").

This patch initializes the splice_write field in file_operations, like
most file systems do, to restore the functionality.

Fixes: 36e2c74 ("fs: don't allow splice read/write without explicit ops")
Signed-off-by: Yangtao Li <frank.li@vivo.com>
Reviewed-by: Viacheslav Dubeyko <slava@dubeyko.com>
Signed-off-by: Viacheslav Dubeyko <slava@dubeyko.com>
Link: https://lore.kernel.org/r/20250529140033.2296791-2-frank.li@vivo.com
Signed-off-by: Viacheslav Dubeyko <slava@dubeyko.com>

Author: bbkzz

fs/hfs/inode.c

@@ -692,6 +692,7 @@ static const struct file_operations hfs_file_operations = {
 	.write_iter	= generic_file_write_iter,
 	.mmap		= generic_file_mmap,
 	.splice_read	= filemap_splice_read,
+	.splice_write	= iter_file_splice_write,
 	.fsync		= hfs_file_fsync,
 	.open		= hfs_file_open,
 	.release	= hfs_file_release,