[OpenMP][Obvious] Fix incompatbile function prototype causing failures

Summary:
This function needs `void` as the arguments to be ABI compatbile with
what is actually defined. This is enforced when doing CUDA separable
linking of the runtime.
GitOrigin-RevId: 8a181f43da2c395daaf30d83248b18d2ab8fe226
diff --git a/libomptarget/test/api/omp_get_num_procs.c b/libomptarget/test/api/omp_get_num_procs.c
index f58274b..e958d0c 100644
--- a/libomptarget/test/api/omp_get_num_procs.c
+++ b/libomptarget/test/api/omp_get_num_procs.c
@@ -2,7 +2,7 @@
 
 #include <stdio.h>
 
-int omp_get_num_procs();
+int omp_get_num_procs(void);
 
 int main() {
   int num_procs;