Mod: fix two errors in examples

tools/drsnoop_example.txt

@@ -38,7 +38,7 @@ whether it is caused by some critical processes or not.
 The -p option can be used to filter on a PID, which is filtered in-kernel. Here
 I've used it with -T to print timestamps:
 
-# ./drsnoop -Tp
+# ./drsnoop -Tp 17491
 TIME(s) COMM PID LAT(ms) PAGES
 107.364115000 summond 17491 0.24 50
 107.364550000 summond 17491 0.26 38
@@ -142,7 +142,7 @@ examples:
  ./drsnoop # trace all direct reclaim
  ./drsnoop -T # include timestamps
  ./drsnoop -U # include UID
- ./drsnoop -P 181 # only trace PID 181
+ ./drsnoop -p 181 # only trace PID 181
  ./drsnoop -t 123 # only trace TID 123
  ./drsnoop -u 1000 # only trace UID 1000
  ./drsnoop -d 10 # trace for 10 seconds only