crypto: scomp - fix req->dst buffer overflow

The req->dst buffer size should be checked before copying from the
scomp_scratch->dst to avoid req->dst buffer overflow problem.

Fixes: 1ab53a77 ("crypto: acomp - add driver-side scomp interface")
Reported-by:  <syzbot+3eff5e51bf1db122a16e@syzkaller.appspotmail.com>
Closes: https://lore.kernel.org/all/0000000000000b05cd060d6b5511@google.com/


Signed-off-by: Chengming Zhou <zhouchengming@bytedance.com>
Reviewed-by: Barry Song <v-songbaohua@oppo.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>