iris: Don't generate Gen10-specific functions

v2: Also update Makefile.sources and Android build files.  Noticed by
Lionel.  Remove more stuff from iris_context.h.

Reviewed-by: Jason Ekstrand <jason@jlekstrand.net> [v1]
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/6899>
4 files changed