fifo8: rename fifo8_peekpop_buf() to fifo8_peekpop_bufptr()

fifo8: rename fifo8_peekpop_buf() to fifo8_peekpop_bufptr()

This is to emphasise that the function returns a pointer to the
internal FIFO buffer.

Signed-off-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Reviewed-by: Octavian Purdila <tavip@google.com>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Tested-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Message-ID: <20240828122258.928947-2-mark.cave-ayland@ilande.co.uk>
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>