Bluetooth: Remove useless `sys_cpu_to_le16` for `uint8_t` type

The target variable is a `uint8_t`. It is not reasonable to pass a
value with `uint16_t` in little-endian format.

Remove `sys_cpu_to_le16`, and pass the value directly.

Signed-off-by: Lyle Zhu <lyle.zhu@nxp.com>