bcachefs: Expand BTREE_NODE_ID

We now have 20 bits for the btree ID in the on disk format - sufficient
for 1 million distinct btrees.

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
This commit is contained in:
Kent Overstreet 2023-06-27 18:01:09 -04:00
commit 4e1430a728