fifo8: honour do_pop argument in fifo8_peekpop_buf()

fifo8: honour do_pop argument in fifo8_peekpop_buf()

Pass the do_pop value from fifo8_peekpop_buf() to fifo8_peekpop_bufptr()
to allow peeks to the FIFO buffer, including adjusting the skip parameter
to handle the case where the internal FIFO buffer wraps around.

Signed-off-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Reviewed-by: Octavian Purdila <tavip@google.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Tested-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Message-ID: <20240828122258.928947-7-mark.cave-ayland@ilande.co.uk>
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>