iw: add multicast rates to IBSS join
iw: add multicast rates to IBSS join

Add multicast rates to IBSS join command.

This patch comes from OpenWRT.

Cc: Felix Fietkau <118ed6118e893d16e8c6e0776e0ebc290952c897@openwrt.org>
Signed-off-by: Bruno Randolf <8baeabad365de895ab58ec0d6dd2c1e27b0ff0b4@einfach.org>

SoluMachines/external_iw,TeamEOS/external_iw,CTU-IIG/802.11p-iw,bw-oss/iw,CTU-IIG/802.11p-iw,OSLL/iw,cozybit/iw,timduru/platform-external-iw,Distrotech/iw,bw-oss/iw,Distrotech/iw,greearb/iw-ct,timduru/platform-external-iw,OSLL/iw,greearb/iw-ct,chunyeow/iw,SoluMachines/external_iw,TeamEOS/external_iw,chunyeow/iw,cozybit/iw