selftests/kcmp: remove unused open mode

Android bionic warns that open modes are ignored if O_CREAT or O_TMPFILE
aren't specified. The permissions for the file are set above:

fd1 = open(kpath, O_RDWR | O_CREAT | O_TRUNC, 0644);

Link: https://lkml.kernel.org/r/[e-mail]
Fixes: d97b46a64674 ("syscalls, x86: add __NR_kcmp syscall")
Signed-off-by: Edward Liaw <[e-mail]>
Reviewed-by: Cyrill Gorcunov <[e-mail]>
Cc: Eric Biederman <[e-mail]>
Cc: Shuah Khan <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>

tools/testing/selftests/kcmp/kcmp_test.c

···
 		ksft_print_header();
 		ksft_set_plan(3);
 
-		fd2 = open(kpath, O_RDWR, 0644);
+		fd2 = open(kpath, O_RDWR);
 		if (fd2 < 0) {
 			perror("Can't open file");
 			ksft_exit_fail();