[pfcwd] Convert polling interval from ms to us in LUA scripts

PFCWD storm detection and restoration LUA scripts require values in microseconds.
Due to recent changes polling interval is now passed in milliseconds by "FlexCounter".
sonic-net/sonic-sairedis#878

Signed-off-by: Volodymyr Samotiy <volodymyrs@nvidia.com>

orchagent/pfc_detect_mellanox.lua

@@ -1,12 +1,12 @@
 -- KEYS - queue IDs
 -- ARGV[1] - counters db index
 -- ARGV[2] - counters table name
--- ARGV[3] - poll time interval
+-- ARGV[3] - poll time interval (milliseconds)
 -- return queue Ids that satisfy criteria
 
 local counters_db = ARGV[1]
 local counters_table_name = ARGV[2]
-local poll_time = tonumber(ARGV[3])
+local poll_time = tonumber(ARGV[3]) * 1000
 
 local rets = {}
 

orchagent/pfc_restore.lua

@@ -1,12 +1,12 @@
 -- KEYS - queue IDs
 -- ARGV[1] - counters db index
 -- ARGV[2] - counters table name
--- ARGV[3] - poll time interval
+-- ARGV[3] - poll time interval (milliseconds)
 -- return queue Ids that satisfy criteria
 
 local counters_db = ARGV[1]
 local counters_table_name = ARGV[2]
-local poll_time = tonumber(ARGV[3])
+local poll_time = tonumber(ARGV[3]) * 1000
 
 local rets = {}