ipv4: igmp: get rid of IGMPV3_{QQIC,MRC} and simplify calculation

ipv4: igmp: get rid of IGMPV3_{QQIC,MRC} and simplify calculation

Get rid of the IGMPV3_MRC macro and use the igmpv3_mrt() API to
calculate the Max Resp Time from the Maximum Response Code.

Similarly, for IGMPV3_QQIC, use the igmpv3_qqi() API to calculate
the Querier's Query Interval from the QQIC field.

Reviewed-by: Nikolay Aleksandrov <razor@blackwall.org>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Signed-off-by: Ujjal Roy <royujjal@gmail.com>
Link: https://patch.msgid.link/20260502131907.987-2-royujjal@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>