brcm: adds support for BCM43341 wifi

brcmfmac: Disable power management

Disable wireless power saving in the brcmfmac WLAN driver. This is a
temporary measure until the connectivity loss resulting from power
saving is resolved.

Signed-off-by: Phil Elwell <phil@raspberrypi.org>

brcmfmac: Use original country code as a fallback

Commit 73345fd2:

    brcmfmac: Configure country code using device specific settings

prevents region codes from working on devices that lack a region code
translation table. In the event of an absent table, preserve the old
behaviour of using the provided code as-is.

Signed-off-by: Phil Elwell <phil@raspberrypi.org>

brcmfmac: Plug memory leak in brcmf_fill_bss_param

See: https://github.com/raspberrypi/linux/issues/1471



Signed-off-by: Phil Elwell <phil@raspberrypi.org>

brcmfmac: do not use internal roaming engine by default

Some evidence of curing disconnects with this disabled, so make it a default.
Can be overridden with module parameter roamoff=0
See: http://projectable.me/optimize-my-pi-wi-fi/



brcmfmac: Change stop_ap sequence

Patch from Broadcom/Cypress to resolve a customer error

Signed-off-by: Phil Elwell <phil@raspberrypi.org>

Revert "brcmfmac: Disable power management"

Shortly after the release of the Pi 3B, a loss of SSH connectivity
over WiFi was traced to the power management handling, so power
management was disabled. And so it has remained ever since.

Enabling power management saves 55mA (~270mW) on a Pi 4B, so is very
much worth the minimal effort of reverting this patch, which was
squashed and rebased many times since then to the commit hash is
meaningless.

Signed-off-by: Phil Elwell <phil@raspberrypi.org>