wifi: brcmfmac: chip: Only disable D11 cores; handle an arbitrary number

At least on BCM4387, the D11 cores are held in reset on cold startup and
firmware expects to release reset itself. Just assert reset here and let
firmware deassert it. Premature deassertion results in the firmware
failing to initialize properly some of the time, with strange AXI bus
errors.

Also, BCM4387 has 3 cores, up from 2. The logic for handling that is in
brcmf_chip_ai_resetcore(), but since we aren't using that any more, just
handle it here.

Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Reviewed-by: Arend van Spriel <arend.vanspriel@broadcom.com>
Signed-off-by: Hector Martin <marcan@marcan.st>
Signed-off-by: Kalle Valo <kvalo@kernel.org>
Link: https://lore.kernel.org/r/20230214092423.15175-1-marcan@marcan.st