openpromfs: finish conversion to the new mount API

openpromfs: finish conversion to the new mount API

[ Upstream commit 8f27829974b025d4df2e78894105d75e3bf349f0 ]

The original mount API conversion inexplicably left out the change
from ->remount_fs to ->reconfigure; do that now.

Fixes: 7ab2fa7693c3 ("vfs: Convert openpromfs to use the new mount API")
Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Link: https://lore.kernel.org/r/90b968aa-c979-420f-ba37-5acc3391b28f@redhat.com
Signed-off-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>