[swss] submodule update (#3925)

9f6efa0 [port/buffer] introduce a sync mechanism to protect port
PG/queue from changes under PFC storm (#1143)
823e426 [aclorch] Enable DSCP rules on IPv6 mirror tables (#1146)
b8745f8 [bitmap_vnet]: Fix removal flow for tunnel route (#1139)
03be983 Increase ip2me CIR/CBR for faster in-band file transfers (#1000)
a4a1d3b [vnet]: Update VNET route table size to 40K for BITMAP
implementation (#1132)
efe142a Fix bug: Wrong condition for mac address (#1142)
7bf63a0 [teammgrd]during warm-reboot teamd need to recover system-id
from saved lacp-pdu (#1003)
8b4cfb6 Cleanup configure.ac from BFN specific code (#1133)
b931751 [teamsyncd]: Add retry logic in teamsyncd to avoid team handler
init failure (#854)

Signed-off-by: Stepan Blyschak <[email protected]>