tools/sched_ext: Add explicit cast from void* in RESIZE_ARRAY()

This fixes the following compilation error when using the header from
C++ code:

  error: assigning to 'struct scx_flux__data_uei_dump *' from
  incompatible type 'void *'

Signed-off-by: Kuba Piecuch <jpiecuch@google.com>
Signed-off-by: Tejun Heo <tj@kernel.org>

tools/sched_ext/include/scx/common.h

@@ -67,6 +67,7 @@ typedef int64_t s64;
 		bpf_map__set_value_size((__skel)->maps.elfsec##_##arr,			\
 				sizeof((__skel)->elfsec##_##arr->arr[0]) * (n));	\
 		(__skel)->elfsec##_##arr =						\
+			(typeof((__skel)->elfsec##_##arr))				\
 			bpf_map__initial_value((__skel)->maps.elfsec##_##arr, &__sz);	\
 	} while (0)