8f1d57c17248 ("amdkfd: don't open-code memdup_user()") mistakenly uses
an uninitialized local pointer, gcc complains:
  drivers/gpu/drm/amd/amdkfd/kfd_chardev.c: In function ‘kfd_ioctl_dbg_address_watch’:
  drivers/gpu/drm/amd/amdkfd/kfd_chardev.c:562:12: warning: ‘args_buff’ may be used uninitialized in this function [-Wmaybe-uninitialized]
    args_buff = memdup_user(args_buff,
                ^
Fix it.
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
 
                return -EINVAL;
 
        /* this is the actual buffer to work with */
-
-       args_buff = memdup_user(args_buff,
+       args_buff = memdup_user(cmd_from_user,
                                args->buf_size_in_bytes - sizeof(*args));
        if (IS_ERR(args_buff))
                return PTR_ERR(args_buff);