Revert "fs: make vfs_fileattr_[get|set] return -EOPNOTSUPP"

Revert "fs: make vfs_fileattr_[get|set] return -EOPNOTSUPP"

This reverts commit 474b155adf3927d2c944423045757b54aa1ca4de.

This patch caused regression in ioctl_setflags(). Underlying filesystems
use EOPNOTSUPP to indicate that flag is not supported. This error is
also gets converted in ioctl_setflags(). Therefore, for unsupported
flags error changed from EOPNOSUPP to ENOIOCTLCMD.

Link: https://lore.kernel.org/linux-xfs/a622643f-1585-40b0-9441-cf7ece176e83@kernel.org/
Signed-off-by: Andrey Albershteyn <aalbersh@kernel.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>