bcachefs: Initialize from_inode members for bch_io_opts

When there is no inode source, all "from_inode" members in the structure
bhc_io_opts should be set false.

Fixes: 7a7c43a0 ("bcachefs: Add bch_io_opts fields for indicating whether the opts came from the inode")
Reported-by:  <syzbot+c17ad4b4367b72a853cb@syzkaller.appspotmail.com>
Closes: https://syzkaller.appspot.com/bug?extid=c17ad4b4367b72a853cb


Signed-off-by: Roxana Nicolescu <nicolescu.roxana@protonmail.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>