crypto: bcm - convert to use crypto_authenc_extractkeys()

Convert the bcm crypto driver to use crypto_authenc_extractkeys() so
that it picks up the fix for broken validation of rtattr::rta_len.

This also fixes the DES weak key check to actually be done on the right
key. (It was checking the authentication key, not the encryption key...)

Fixes: 9d12ba86f818 ("crypto: brcm - Add Broadcom SPU driver")
Cc: <stable@vger.kernel.org> # v4.11+
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
diff --git a/drivers/crypto/Kconfig b/drivers/crypto/Kconfig
index 5a90075..0be55fc 100644
--- a/drivers/crypto/Kconfig
+++ b/drivers/crypto/Kconfig
@@ -692,6 +692,7 @@
 	depends on ARCH_BCM_IPROC
 	depends on MAILBOX
 	default m
+	select CRYPTO_AUTHENC
 	select CRYPTO_DES
 	select CRYPTO_MD5
 	select CRYPTO_SHA1