image: fit: Use stack allocation macro

The documentation above the DEFINE_ALIGN_BUFFER says it's for use
outside functions, but we're inside one.

Instead use ALLOC_CACHE_ALIGN_BUFFER, the stack based macro, which also
includes the cache alignment.

Fixes: b583348ca8c8 ("image: fit: Align hash output buffers")
Signed-off-by: Joel Stanley <joel@jms.id.au>
Tested-by: Chia-Wei Wang <chiawei_wang@aspeedtech.com>
Reviewed-by: Sean Anderson <sean.anderson@seco.com>
diff --git a/boot/image-fit.c b/boot/image-fit.c
index f57d97f..df3e5df 100644
--- a/boot/image-fit.c
+++ b/boot/image-fit.c
@@ -1264,8 +1264,7 @@
 static int fit_image_check_hash(const void *fit, int noffset, const void *data,
 				size_t size, char **err_msgp)
 {
-	DEFINE_ALIGN_BUFFER(uint8_t, value, FIT_MAX_HASH_LEN,
-			    ARCH_DMA_MINALIGN);
+	ALLOC_CACHE_ALIGN_BUFFER(uint8_t, value, FIT_MAX_HASH_LEN);
 	int value_len;
 	const char *algo;
 	uint8_t *fit_value;