Delete libva-tpi and libva-egl backends

Delete libva-tpi and libva-egl backends

The APIs/data structures defined in va_tpi.h and va_egl.h are used
to implement buffer sharing between libva and the 3rd party libraries.
We have an official buffer sharing machnism in VA core, so libva-tpi and
libva-egl are unnecessary any more.

However va_egl.h or va_tpi.h is included uselessly in a few places,
e.g. https://github.com/01org/libyami/blob/apache/vaapi/vaapidisplay.h#L22
So va_egl.h and va_tpi.h are kept with a deprecation warning message.

Signed-off-by: Xiang, Haihao <haihao.xiang@intel.com>