Add RNG driver

[andelf]

This pull request includes the following changes:

1. Update hpm-metapac to the latest version
2. Add RNG (Random Number Generator) driver with implementation of rand_core traits:
   • next_u32
   • next_u64
   • fill_bytes

Notes on RNG Implementation:

• Async RNG driver implementation is currently not feasible due to hardware design limitations.

Possible Issues:

The RNG interrupt functionality appears to be non-functional due to the following reasons:

• Lack of a FIFO-ready signal (FUFMOD usage unclear)
• Absence of explicit interrupt flags
• Subsequent interrupts after the initial one fail to trigger

Further investigation and potential workarounds for these issues may be needed in future updates.

[andelf]

Demo:

use rand_core::RngCore;
use {defmt_rtt as _, hpm_hal as hal};

#[embassy_executor::main(entry = "hpm_hal::entry")]
async fn main(_spawner: embassy_executor::Spawner) -> ! {
    let p = hal::init(Default::default());

    let mut rng = hal::rng::Rng::new(p.RNG).unwrap();
    let mut buf = [0u8; 20];

    loop {
        rng.fill_bytes(&mut buf);

        defmt::println!("buf: {:?}", buf);
    }
}

#[panic_handler]
fn panic(info: &core::panic::PanicInfo) -> ! {
    defmt::panic!("{}", defmt::Debug2Format(info));
}

[HaoboGu]

lgtm