k_timer: Don't allocate dynamic timers by default

Most apps run fine with static k_timer objects.  Don't pay the cost
for the timer pool if no one asks for it.

Also turn off the allocate/free API in the header if it can't possibly
work at runtime as it's an obviously-detectable error that would
otherwise be visible only at runtime.

Change-Id: I492e6e01c4213e3544f707247eea6e4bc601fefd
Signed-off-by: Andy Ross <andrew.j.ross@intel.com>
3 files changed