MINOR: quic: strengthen qc_release_frm()

MINOR: quic: strengthen qc_release_frm()

quic_frame is the type used to represent frames emitted in a QUIC Tx
packet. Each frame is attached to a packet, and can also be linked to
other frames from the the same packet, or duplicated frames for
retransmission. As such, quic_frame free operation is a tedious process.

qc_release_frm() has been implemented to ensure quic_frame is always
properly freed after detaching from all its list attach point. One
particular point is to ensure that when a frame is released, the frame
origin and all origin copies, including the current <frm> are flagged as
acked and detached from the reflist. Add a BUG_ON() to ensure this loop
is properly conducted when dealing with the current <frm> instance.