To avoid namespace collisions, rename get_crypt_info() to
fscrypt_get_crypt_info().  The function is only used inside the
fs/crypto directory, so declare it in the new header file,
fscrypt_private.h.
Signed-off-by: NTheodore Ts'o <tytso@mit.edu>
Reviewed-by: NEric Biggers <ebiggers@google.com>