selftests/mm: virtual_address_range: Switch to ksft_exit_fail_msg

mmap() must not succeed in validate_lower_address_hint(), for if it does,
it is a bug in mmap() itself.  Reflect this behaviour with
ksft_exit_fail_msg().  While at it, do some formatting changes.

Link: https://lkml.kernel.org/r/20240314122250.68534-1-dev.jain@arm.comSigned-off-by: Dev Jain <dev.jain@arm.com>
Reviewed-by: Muhammad Usama Anjum <usama.anjum@collabora.com>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

tools/testing/selftests/mm/virtual_address_range.c

@@ -108,10 +108,8 @@ int main(int argc, char *argv[])
 			      MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
 
 		if (ptr[i] == MAP_FAILED) {
-			if (validate_lower_address_hint()) {
-				ksft_test_result_skip("Memory constraint not fulfilled\n");
-				ksft_finished();
-			}
+			if (validate_lower_address_hint())
+				ksft_exit_fail_msg("mmap unexpectedly succeeded with hint\n");
 			break;
 		}