wifi: brcmsmac: phy: Remove unreachable code

wlc_phy_txpwr_srom_read_nphy() in wlc_phy_attach_nphy() can not
return false, so it's impossible to get true value in this
if-statement. Also change those functions return types to void
since no one using it.

Found by Linux Verification Center (linuxtesting.org) with SVACE.

Signed-off-by: Artem Chernyshev <artem.chernyshev@red-soft.ru>
Reviewed-by: Jonas Gorski <jonas.gorski@gmail.com>
Signed-off-by: Kalle Valo <kvalo@kernel.org>
Link: https://msgid.link/20230814093621.289754-1-artem.chernyshev@red-soft.ru

brcmsmac: switch phy source files to using SPDX license identifier

With ISC license text in place under the LICENSES folder switch
to using the SPDX license identifier to refer to the ISC license.

Reviewed-by: Hante Meuleman <hante.meuleman@broadcom.com>
Reviewed-by: Pieter-Paul Giesberts <pieter-paul.giesberts@broadcom.com>
Reviewed-by: Franky Lin <franky.lin@broadcom.com>
Signed-off-by: Arend van Spriel <arend.vanspriel@broadcom.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>

brcmsmac: Use cordic-related macros from common cordic library

Current driver includes macro that is available from general cordic
library. Use that and drop unused duplicate and unneeded internal
definitions.

Signed-off-by: Priit Laes <plaes@plaes.org>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>

brcm80211: move under broadcom vendor directory

Part of reorganising wireless drivers directory and Kconfig. Note that I had to
edit Makefiles from subdirectories to use the new location.

Signed-off-by: Kalle Valo <kvalo@codeaurora.org>