Move the hwcomposer vsync thread into common

This is so that the new cutf_cvm hwcomposer will be able to access
the vsync thread, since the code is shared.  The other piece of
this change is to shrink the data portion of the hwcomposer struct
into its own struct, since this portion will be shared between the
cutf_ivsh and cutf_cvm hwcomposers and passed to the vsync thread.

Bug: 122976892
Change-Id: I33187de1f1a022c4c05b7c432c0d376337a3cfc3