bcachefs: Fix -Wincompatible-function-pointer-types-strict from key_invalid callbacks

When building bcachefs with -Wincompatible-function-pointer-types-strict,
a clang warning designed to catch issues with mismatched function
pointer types, which will be fatal at runtime due to kernel Control Flow
Integrity (kCFI), there are several instances along the lines of:

  fs/bcachefs/bkey_methods.c:118:2: error: incompatible function pointer types initializing 'int (*)(const struct bch_fs *, struct bkey_s_c, enum bkey_invalid_flags, struct printbuf *)' with an expression of type 'int (const struct bch_fs *, struct bkey_s_c, unsigned int, struct printbuf *)' [-Werror,-Wincompatible-function-pointer-types-strict]
    118 |         BCH_BKEY_TYPES()
        |         ^~~~~~~~~~~~~~~~
  fs/bcachefs/bcachefs_format.h:342:2: note: expanded from macro 'BCH_BKEY_TYPES'
    342 |         x(deleted,              0)                      \
        |         ^~~~~~~~~~~~~~~~~~~~~~~~~~
  fs/bcachefs/bkey_methods.c:117:41: note: expanded from macro 'x'
    117 | #define x(name, nr) [KEY_TYPE_##name]   = bch2_bkey_ops_##name,
        |                                           ^~~~~~~~~~~~~~~~~~~~
  <scratch space>:206:1: note: expanded from here
    206 | bch2_bkey_ops_deleted
        | ^~~~~~~~~~~~~~~~~~~~~
  fs/bcachefs/bkey_methods.c:34:17: note: expanded from macro 'bch2_bkey_ops_deleted'
     34 |         .key_invalid = deleted_key_invalid,             \
        |                        ^~~~~~~~~~~~~~~~~~~

The flags parameter should be of type 'enum bkey_invalid_flags', not
'unsigned int'. Adjust the type everywhere so that there is no more
warning.

Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>