emugl: Simplify GLESv1 dispatch sources.

This simplifies the sources by re-using the auto-generated declarations
from the decoder, instead of using hard-coded duplicates, which are prone
to error.

Note that this is what the GLESv2 dispatch implementation already does.

Change-Id: Iab82bccd47686573e6a5bc5cf6c1e660c268730b
2 files changed