wifi: brcmsmac: advertise MFP_CAPABLE to enable WPA3

After being asked about support for WPA3 for BCM43224 chipset it
was found that all it takes is setting the MFP_CAPABLE flag and
mac80211 will take care of all that is needed [1].

Link: https://lore.kernel.org/linux-wireless/20200526155909.5807-2-Larry.Finger@lwfinger.net/ [1]
Signed-off-by: Arend van Spriel <arend.vanspriel@broadcom.com>
Tested-by: Reijer Boekhoff <reijerboekhoff@protonmail.com>
Signed-off-by: Kalle Valo <kvalo@kernel.org>
Link: https://patch.msgid.link/20240617122609.349582-1-arend.vanspriel@broadcom.com