Bluetooth: Host: Add a validation for `hci_le_read_max_data_len()`

Check max_tx_octects and max_tx_time are in the valid range, according
to the BT Core spec 5.4 [Vol 4, Part E, 7.8.46]
Fix #70472

Signed-off-by: Sungwoo Kim <iam@sung-woo.kim>