[nrf fromlist] drivers: flash: nrf_qspi_nor: reject zero length transfer

The check for small transfers inadvertently allowed a transfer of zero
bytes, which should be an error (invalid parameter).

Signed-off-by: Peter Bigot <[email protected]>
Signed-off-by: Sigvart Hovland <[email protected]>
(cherry picked from commit 7d847b4)

Author: pabigot

drivers/flash/nrf_qspi_nor.c

@@ -503,7 +503,7 @@ static int qspi_nor_read(struct device *dev, off_t addr, void *dest,
 	/* Since the QSPI driver requires data to be at least 4 bytes we need
 	 * to use a 4 byte buffer for reads smaller than 4 bytes.
 	 */
-	if (size < 4U) {
+	if ((size > 0) && (size < 4U)) {
 		dest = buf;
 		size = sizeof(buf);
 	} else if ((size % 4U) != 0) {