Bluetooth: hci_nxp: Improve MAC address uniqueness using CRC-32 hash

The previous method of deriving the local MAC address from the MCU's
Unique ID (UID) by slicing the last 3 bytes had two issues:

1.  **Low Entropy:** Risk of address collision because only a small
    portion of the UID was used, and this portion may not vary much.
2.  **Offset Error:** An incorrect offset calculation could copy
    non-intended bytes.

This commit resolves both issues by replacing the slice operation
with a **CRC-32 hash** over the **entire 16-byte UID**.

The lower 3 bytes (24 bits) of the resulting CRC-32 are used as the
local part of the MAC address, maximizing randomization and ensuring
a high probability of uniqueness across all devices.

Signed-off-by: Badr Bacem KAABIA <badrbacemkaabia@gmail.com>