crypto: amlogic - ensure error variable err is set before returning it

Currently when the call to crypto_engine_alloc_init fails the error
return path returns an uninitialized value in the variable err. Fix
this by setting err to -ENOMEM.

Addresses-Coverity: ("Uninitialized scalar variable")
Fixes: 48fe583f ("crypto: amlogic - Add crypto accelerator for amlogic GXL")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Acked-by: Corentin Labbe <clabbe@baylibre.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

drivers/crypto/amlogic/amlogic-gxl-core.c

@@ -162,6 +162,7 @@ static int meson_allocate_chanlist(struct meson_dev *mc)
 		if (!mc->chanlist[i].engine) {
 			dev_err(mc->dev, "Cannot allocate engine\n");
 			i--;
+			err = -ENOMEM;
 			goto error_engine;
 		}
 		err = crypto_engine_start(mc->chanlist[i].engine);