cfi_flash: Fix bug in flash_isset() to use correct 32bit function

This bug was detected on the LWMON5 target which has 2 Intel 16bit wide
flash chips connected to a 32bit wide port.

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

drivers/mtd/cfi_flash.c

@@ -527,7 +527,7 @@ static int flash_isset (flash_info_t * info, flash_sect_t sect,
 		retval = ((flash_read16(addr) & cword.w) == cword.w);
 		break;
 	case FLASH_CFI_32BIT:
-		retval = ((flash_read16(addr) & cword.l) == cword.l);
+		retval = ((flash_read32(addr) & cword.l) == cword.l);
 		break;
 	case FLASH_CFI_64BIT:
 		retval = ((flash_read64(addr) & cword.ll) == cword.ll);