net: uip: Added missing function prototypes to rtimer

Real timer implementation needs function prototypes.
This is just to satisfy the compiler. Needs more TLC.

Change-Id: I39baa7cfe69d28aa1f330089e22144df286c0a0d
Signed-off-by: Jukka Rissanen <jukka.rissanen@linux.intel.com>
1 file changed