drivers/flash/soc_flash_mcux: adjust alignment logic

The current alignment logic does not work as expected if given unaligned
values, resulting in a skip of the first word. The length also has to
take into account the starting address: for example, asking for 2 bytes
at offset 3 should actually check 8 bytes.

This patch adjusts the logic so that it always includes the first and
the last word of the input area.

Signed-off-by: Luca Burelli <l.burelli@arduino.cc>

drivers/flash/soc_flash_mcux.c

@@ -221,7 +221,9 @@ static int flash_mcux_read(const struct device *dev, off_t offset,
 		/* Check id the ECC issue is due to the Flash being erased
 		 * ("addr" and "len" must be word-aligned for this call).
 		 */
-		rc = FLASH_VerifyErase(&priv->config, ((addr + 0x3) & ~0x3),  ((len + 0x3) & ~0x3));
+		rc = FLASH_VerifyErase(&priv->config,
+				       ROUND_DOWN(addr, 4),
+				       ROUND_DOWN(addr + len + 3, 4) - ROUND_DOWN(addr, 4));
 		if (rc == kStatus_FLASH_Success) {
 			rc = -ENODATA;
 		} else {