fixed some warnings in mono-proclib.c

mono-proclib.c: In function ‘get_cpu_times’:
mono-proclib.c:600:24: warning: ‘sirq_ticks’ may be used uninitialized in this function [-Wmaybe-uninitialized]
   *sirq = (sirq_ticks) * 10000000 / hz;
                        ^
mono-proclib.c:598:22: warning: ‘irq_ticks’ may be used uninitialized in this function [-Wmaybe-uninitialized]
   *irq = (irq_ticks) * 10000000 / hz;
                      ^
mono-proclib.c:602:24: warning: ‘idle_ticks’ may be used uninitialized in this function [-Wmaybe-uninitialized]
   *idle = (idle_ticks) * 10000000 / hz;
                        ^
mono-proclib.c:596:29: warning: ‘system_ticks’ may be used uninitialized in this function [-Wmaybe-uninitialized]
   *systemt = (system_ticks) * 10000000 / hz;
                             ^
mono-proclib.c:594:23: warning: ‘nice_ticks’ may be used uninitialized in this function [-Wmaybe-uninitialized]
   *user = (user_ticks + nice_ticks) * 10000000 / hz;
                       ^
mono-proclib.c:594:23: warning: ‘user_ticks’ may be used uninitialized in this function [-Wmaybe-uninitialized]