Cleanups suggested by Guenter Roeck, falling into 4 categories:
* Swapping test orders, because if (var == CONSTANT) is much easier to
  read than if (CONSTANT == var).
* Simplifying comparisons with 0.
* Dropping unneeded masks.
* Dropping unneeded parentheses and curly braces.
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Acked-by: Guenter Roeck <guenter.roeck@ericsson.com>