scripts: west: commands: completion: add twister --log-level completion

Add bash tab-completion for for the newly introduced "west twister
--log-level" arguments.

Signed-off-by: Henrik Brix Andersen <hebad@vestas.com>

scripts/west_commands/completion/west-completion.bash

@@ -1064,6 +1064,7 @@ __comp_west_twister()
  --coverage-tool
  --exclude-platform -P
  --filter
+ --log-level
  --platform -p
  --runtime-artifact-cleanup -M
  "
@@ -1114,6 +1115,11 @@ __comp_west_twister()
  return
  ;;
 
+ --log-level)
+ __set_comp "CRITICAL DEBUG ERROR INFO NOTSET WARNING"
+ return
+ ;;
+
  --runtime-artifact-cleanup|-M)
  __set_comp "all pass"
  return