wifi: brcm80211: Remove unused functions

wifi: brcm80211: Remove unused functions

This is a subset of unused functions in bcrmsmac phy_cmn.c,
They're unused since the original 2010
commit a9533e7ea3c4 ("Staging: Add initial release of brcm80211 - Broadcom
802.11n wireless LAN driver.")

Remove them.
Then remove two more functions in phy_n.c that were only used
by the ones just removed.

Signed-off-by: Dr. David Alan Gilbert <linux@treblig.org>
Acked-by: Arend van Spriel <arend.vanspriel@broadcom.com>>
Link: https://patch.msgid.link/20250626140812.56700-2-linux@treblig.org
Signed-off-by: Johannes Berg <johannes.berg@intel.com>