crypto: mxs-dcp - remove set but not used variable 'fini'

Fixes gcc '-Wunused-but-set-variable' warning:

drivers/crypto/mxs-dcp.c: In function 'dcp_chan_thread_sha':
drivers/crypto/mxs-dcp.c:707:11: warning:
 variable 'fini' set but not used [-Wunused-but-set-variable]

It's not used since commit d80771c0 ("crypto: mxs-dcp - Fix wait
logic on chan threads"),so can be removed.

Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>