openssl: fix building on riscv32

On riscv32 configurations OpenSSL fails to build with "undefined
reference to `__atomic_foo'" kind of errors. Change OpenSSL recipe to
use linux-latomic configuration instead of linux-generic32.

Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
(cherry picked from commit e8ce80fc)
Signed-off-by: Steve Sakoman <steve@sakoman.com>