greybus: tracing: fix "make check" warnings

Some of the trace buffer fields were defined as Booleans.  This
leads to two problems reported by "make check":
    - the __field() macro (or some descendent macro) performs
      a sizeof(bool) operation, which results in a warning
    - The TP_printk() macro, which specifies a printf() style
      format string, produces a warning when one attempts to
      format a Boolean as an integer.
Fix both problems implicitly converting Boolean values from the data
structures into integers in the trace buffer.

Signed-off-by: Alex Elder <elder@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>