glapi: Remove static dispatch for functions that didn't exist in 10.3

glapi: Remove static dispatch for functions that didn't exist in 10.3

Comparing the output of

    nm libGL.so | grep ' T gl[^X]' | sed 's/.* T //'

between 10.3.7 and this commit, the only change is the removal of
glFramebufferTextureFaceARB.  This function was removed a couple commits
previously.

glClipControl was, at the time 10.3 shipped, a very new function.  It
was added by GL_ARB_clip_control.  That extension was ratified by the
Khronos Board of Promoters on August 7, 2014.  It's less than a year
old, and I don't think it's is likely that there are many applications
using that extension... much less statically linking with the function.

Signed-off-by: Ian Romanick <ian.d.romanick@intel.com>
Reviewed-by: Emil Velikov <emil.l.velikov@gmail.com>