crypto: img-hash - Use unregister_ahashes in img_{un}register_algs

crypto: img-hash - Use unregister_ahashes in img_{un}register_algs

Replace the for loops with calls to crypto_unregister_ahashes(). In
img_register_algs(), return 'err' immediately and remove the goto
statement to simplify the error handling code.

Convert img_unregister_algs() to a void function since its return value
is never used.

Signed-off-by: Thorsten Blum <thorsten.blum@linux.dev>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>