qcacld-3.0: Free a bunch of pkts at once

It is too bad to do a tight loop every adding pkt. When the hotspot is turned on, I notice that the
htt_htc_misc_pkt_list_trim() function consumes at least 5% of CPU time. By caching the head of pkt
queue and freeing multiple pkts at once to reduce CPU consumption.

Signed-off-by: Julian Liu <wlootlxt123@gmail.com>
Signed-off-by: mcdachpappe <noreference@web.de>