ANDROID: fix wakeup reason findings

The 0-day test bot found three minor issues in the wakeup_reason
enhancements patch, including two undeclared functions that should have
been static, an allegedly uninitialized pointer (which is actually set
in the line immediately prior to cppcheck's complaint), and a type
mismatch when printing timespec64 fields on a 32-bit build.

These changes address those findings.

Fixes: e7b509cf ("ANDROID: power: wakeup_reason: wake reason
enhancements")
Bug: 153727431
Reported-by: kbuild test robot <lkp@intel.com>
Change-Id: I9194f85d0ca7921461866b73dc24e1783b1da6c6
Signed-off-by: Kelly Rossmoyer <krossmo@google.com>