kernel: comply to coding guidelines MISRA C:2012 Rule 14.4

MISRA C:2012 Rule 14.4 (The controlling expression of an if statement
and the controlling expression of an iteration-statement shall have
essentially Boolean type.)

Use `bool' instead of `int' to represent Boolean values.
Use `do { ... } while (false)' instead of `do { ... } while (0)'.
Use comparisons with zero instead of implicitly testing integers.

This commit is a subset of the original commit:
5d02614e34a86b549c7707d3d9f0984bc3a5f22a

Signed-off-by: Simon Hein <SHein@baumer.com>
5 files changed