bcachefs: Explicitly select CRYPTO from BCACHEFS_FS

bcachefs: Explicitly select CRYPTO from BCACHEFS_FS

Explicitly select CRYPTO from BCACHEFS_FS, so that this dependency of
CRYPTO_SHA256, CRYPTO_CHACHA20, and CRYPTO_POLY1305 (which are also
selected) is satisfied.  Currently this dependency is satisfied
indirectly via LIBCRC32C, but this is fragile and is planned to change
(https://lore.kernel.org/r/20241021002935.325878-13-ebiggers@kernel.org).

Acked-by: Kent Overstreet <kent.overstreet@linux.dev>
Link: https://lore.kernel.org/r/20241202010844.144356-15-ebiggers@kernel.org
Signed-off-by: Eric Biggers <ebiggers@google.com>