uacce: make uacce_class constant

Now that the driver core allows for struct class to be in read-only
memory, we should make all 'class' structures declared at build time
placing them into read-only memory, instead of having to be dynamically
allocated at runtime.

Cc: Zhou Wang <wangzhou1@hisilicon.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: linux-accelerators@lists.ozlabs.org
Tested-by: Zhangfei Gao <zhangfei.gao@linaro.org>
Link: https://lore.kernel.org/r/2023102458-designate-vicinity-4c86@gregkh
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>