trace: Add trace points for tasklet entry/exit

Tasklets are supposed to finish their work quickly and
should not block the current running process, but it is not
guaranteed that. Currently softirq_entry/exit can be used to
know total tasklets execution time, but not helpful to track
individual tasklet's execution time. With that we can't find
any culprit tasklet function, which is taking more time.

Add {hi}-tasklet_entry/exit trace point support to track
individual tasklet execution.

Change-Id: I3496d15f64d020916774e673ccb4a8116ea2f2c9
Signed-off-by: Lingutla Chandrasekhar <clingutla@codeaurora.org>