selftests/vm: madv_populate: fix missing MADV_POPULATE_(READ|WRITE) definitions

The tests fail to compile in some environments (e.g., Debian 11.5 on x86).
Let's simply conditionally define MADV_POPULATE_(READ|WRITE) if not
already defined, similar to how the khugepaged.c test handles it.

Link: https://lkml.kernel.org/r/[email protected]
Fixes: 39b2e5c ("selftests/vm: make MADV_POPULATE_(READ|WRITE) use in-tree headers")
Signed-off-by: David Hildenbrand <[email protected]>
Cc: Shuah Khan <[email protected]>
Cc: Yang Li <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

Author: davidhildenbrand

tools/testing/selftests/vm/madv_populate.c

@@ -20,6 +20,13 @@
 #include "../kselftest.h"
 #include "vm_util.h"
 
+#ifndef MADV_POPULATE_READ
+#define MADV_POPULATE_READ	22
+#endif /* MADV_POPULATE_READ */
+#ifndef MADV_POPULATE_WRITE
+#define MADV_POPULATE_WRITE	23
+#endif /* MADV_POPULATE_WRITE */
+
 /*
  * For now, we're using 2 MiB of private anonymous memory for all tests.
  */