tracing: Apply upper limit of pid to prevent buffer overflow

tracing: Apply upper limit of pid to prevent buffer overflow

A member array `map_pid_to_cmdline` is allocated as much as
PID_MAX_DEFAULT. There is no consideration when a given pid
exceeds PID_MAX_DEFAULT which can make buffer overflow.

This patch handles such cases by just returning -1 for a case
that the given pid exceeds PID_MAX_DEFAULT. For such cases,
the user of trace loses tgid information for a given pid.

Change-Id: I589eda187490eddbd26fa5300a288097842d9af0
Signed-off-by: Sung-hun Kim <sfoon.kim@samsung.com>