Use more appropriate type in cb_handle_t::validate.

The interface specified by the HWC hal includes const native_handle
(through a typedef) which makes it annoying to const_cast away in order
to call validate.

Validate does not change the handle so this is safe.

Change-Id: I78b2997eb24074c186ab2d497b2faf332c7f4a85
1 file changed