brcmfmac: drop chip id from debug messages

The chip ID was already printed out at the time when debug message about
the changed F2 watermark is printed, hence let's drop the unnecessary part
of the debug messages. This cleans code a tad and also allows to re-use
the F2 watermark debug messages by multiple chips.

Suggested-by: Arend van Spriel <arend.vanspriel@broadcom.com>
Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Link: https://lore.kernel.org/r/20200830191439.10017-3-digetx@gmail.com