cfi_flash: Use flash_read32() in sector_erased()

The function sector_erased() is modified to not use pointer
access, but to use the correct accessor functions. This fixes a
problem on the t3corp board with the Xilinx DS617 flash chips. Here
a board specific accessor function is needed to read from flash
in 32bit mode. This patch enables such an operation mode.

Signed-off-by: Stefan Roese <sr@denx.de>

drivers/mtd/cfi_flash.c

@@ -1112,18 +1112,18 @@ static int sector_erased(flash_info_t *info, int i)
 {
 	int k;
 	int size;
-	volatile unsigned long *flash;
+	u32 *flash;
 
 	/*
 	 * Check if whole sector is erased
 	 */
 	size = flash_sector_size(info, i);
-	flash = (volatile unsigned long *) info->start[i];
+	flash = (u32 *)info->start[i];
 	/* divide by 4 for longword access */
 	size = size >> 2;
 
 	for (k = 0; k < size; k++) {
-		if (*flash++ != 0xffffffff)
+		if (flash_read32(flash++) != 0xffffffff)
 			return 0;	/* not erased */
 	}