crypto: cavium/nitrox - Replace GFP_ATOMIC with GFP_KERNEL in crypto_alloc_context()

crypto_alloc_context() is only called by nitrox_skcipher_init(), which is
never called in atomic context.

crypto_alloc_context() calls dma_pool_alloc() with GFP_ATOMIC,
which is not necessary.
GFP_ATOMIC can be replaced with GFP_KERNEL.

This is found by a static analysis tool named DCNS written by myself.
I also manually check the kernel code before reporting it.

Signed-off-by: Jia-Ju Bai <baijiaju1990@gmail.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

drivers/crypto/cavium/nitrox/nitrox_lib.c

@@ -148,7 +148,7 @@ void *crypto_alloc_context(struct nitrox_device *ndev)
 	void *vaddr;
 	dma_addr_t dma;
 
-	vaddr = dma_pool_alloc(ndev->ctx_pool, (GFP_ATOMIC | __GFP_ZERO), &dma);
+	vaddr = dma_pool_alloc(ndev->ctx_pool, (GFP_KERNEL | __GFP_ZERO), &dma);
 	if (!vaddr)
 		return NULL;