crypto: sun4i_ss_prng - convert lock to _bh in sun4i_ss_prng_generate

Lockdep detects a possible deadlock in sun4i_ss_prng_generate() and
throws an "inconsistent {SOFTIRQ-ON-W} -> {IN-SOFTIRQ-W} usage" warning.
Disabling softirqs to fix this.

Fixes: b8ae5c7 ("crypto: sun4i-ss - support the Security System PRNG")
Signed-off-by: Artem Savkov <artem.savkov@gmail.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

drivers/crypto/sunxi-ss/sun4i-ss-prng.c

@@ -28,7 +28,7 @@ int sun4i_ss_prng_generate(struct crypto_rng *tfm, const u8 *src,
 	algt = container_of(alg, struct sun4i_ss_alg_template, alg.rng);
 	ss = algt->ss;
 
-	spin_lock(&ss->slock);
+	spin_lock_bh(&ss->slock);
 
 	writel(mode, ss->base + SS_CTL);
 
@@ -51,6 +51,6 @@ int sun4i_ss_prng_generate(struct crypto_rng *tfm, const u8 *src,
 	}
 
 	writel(0, ss->base + SS_CTL);
-	spin_unlock(&ss->slock);
+	spin_unlock_bh(&ss->slock);
 	return 0;
 }