mesa: Generate invalid operation in glGenerateMipMap for integer textures

mesa: Generate invalid operation in glGenerateMipMap for integer textures

Khronos has reached a conclusion and disallowed following texture formats in
glGenerateMipMap():
 (a) ASTC textures
 (b) integer internal formats (e.g., RGBA8UI, RG16I)
 (c) textures with stencil formats (e.g., STENCIL_INDEX8)
 (d) textures with packed depth/stencil formats (e.g, DEPTH24_STENCIL8)

https://cvs.khronos.org/bugzilla/show_bug.cgi?id=9471

Note: This is a candidate for stable branches.
Signed-off-by: Anuj Phogat <anuj.phogat@gmail.com>
Reviewed-by: Brian Paul <brianp@vmware.com>