bcachefs: drop packed, aligned from bkey_inode_buf

Unnecessary here, and this broke the rust bindings:

error[E0588]: packed type cannot transitively contain a `#[repr(align)]` type
     --> /build/source/target/release/build/bch_bindgen-9445b24c90aca2a3/out/bcachefs.rs:29025:1
      |
29025 | pub struct bkey_i_inode_v3 {
      | ^^^^^^^^^^^^^^^^^^^^^^^^^^
      |
note: `bch_inode_v3` has a `#[repr(align)]` attribute
     --> /build/source/target/release/build/bch_bindgen-9445b24c90aca2a3/out/bcachefs.rs:8949:1
      |
8949  | pub struct bch_inode_v3 {
      | ^^^^^^^^^^^^^^^^^^^^^^^

error[E0588]: packed type cannot transitively contain a `#[repr(align)]` type
     --> /build/source/target/release/build/bch_bindgen-9445b24c90aca2a3/out/bcachefs.rs:32826:1
      |
32826 | pub struct bkey_inode_buf {
      | ^^^^^^^^^^^^^^^^^^^^^^^^^
      |
note: `bch_inode_v3` has a `#[repr(align)]` attribute
     --> /build/source/target/release/build/bch_bindgen-9445b24c90aca2a3/out/bcachefs.rs:8949:1
      |
8949  | pub struct bch_inode_v3 {
      | ^^^^^^^^^^^^^^^^^^^^^^^
note: `bkey_inode_buf` contains a field of type `bkey_i_inode_v3`
     --> /build/source/target/release/build/bch_bindgen-9445b24c90aca2a3/out/bcachefs.rs:32827:9
      |
32827 |     pub inode: bkey_i_inode_v3,
      |         ^^^^^
note: ...which contains a field of type `bch_inode_v3`
     --> /build/source/target/release/build/bch_bindgen-9445b24c90aca2a3/out/bcachefs.rs:29027:9
      |
29027 |     pub v: bch_inode_v3,
      |         ^

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>