tinycrypt: Fix style issues

This commit solves some style issues found at the
tests/include/test_utils.h file:

- Lines over 80 characters
- Unused arguments
- Missing {} in if-else

Change-Id: Ifaee81ec7c57a250b2c368b2efda38dc69d02c81
Signed-off-by: Flavio Santes <flavio.santes@intel.com>