fix: tracepoint: Optimize using static_call() (v5.10)

fix: tracepoint: Optimize using static_call() (v5.10)

See upstream commit :

  commit d25e37d89dd2f41d7acae0429039d2f0ae8b4a07
  Author: Steven Rostedt (VMware) <rostedt@goodmis.org>
  Date:   Tue Aug 18 15:57:52 2020 +0200

    tracepoint: Optimize using static_call()

    Currently the tracepoint site will iterate a vector and issue indirect
    calls to however many handlers are registered (ie. the vector is
    long).

    Using static_call() it is possible to optimize this for the common
    case of only having a single handler registered. In this case the
    static_call() can directly call this handler. Otherwise, if the vector
    is longer than 1, call a function that iterates the whole vector like
    the current code.

Change-Id: I739dd84d62cc1a821b8bd8acff74fa29aa25d22f
Signed-off-by: Michael Jeanson <mjeanson@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>