fs: fat: Fix cache align error message in fatwrite

Use of malloc of do_fat_write() causes cache error on ARM v7 platforms.
Perhaps, the same problem will occur at any other CPUs.
This replaces malloc with memalign to fix cache buffer alignment.

Signed-off-by: Nobuhiro Iwamatsu <nobuhiro.iwamatsu.yj@renesas.com>
Signed-off-by: Yoshiyuki Ito <yoshiyuki.ito.ub@renesas.com>
Tested-by: Hector Palacios <hector.palacios@digi.com>

fs/fat/fat_write.c

@@ -952,7 +952,7 @@ static int do_fat_write(const char *filename, void *buffer,
 	}
 
 	mydata->fatbufnum = -1;
-	mydata->fatbuf = malloc(FATBUFSIZE);
+	mydata->fatbuf = memalign(ARCH_DMA_MINALIGN, FATBUFSIZE);
 	if (mydata->fatbuf == NULL) {
 		debug("Error: allocating memory\n");
 		return -1;