crypto: bcm - Fix pointer arithmetic

In spu2_dump_omd() value of ptr is increased by ciph_key_len
instead of hash_iv_len which could lead to going beyond the
buffer boundaries.
Fix this bug by changing ciph_key_len to hash_iv_len.

Found by Linux Verification Center (linuxtesting.org) with SVACE.

Fixes: 9d12ba86 ("crypto: brcm - Add Broadcom SPU driver")
Signed-off-by: Aleksandr Mishin <amishin@t-argos.ru>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>