i965: Eric Anholt's patch for bumping up texture sizes

i965: Eric Anholt's patch for bumping up texture sizes

I'm committing this because it fixes a conform failure; the failure occurs
on the TextureProxy test, where the test attempts to create proxy textures
at every level, but fails at the last level (border == 1, width == 1,
height == 1) because it's beyond MAX_TEXTURE_LEVELS.

Eric's original comment was:

idr said that in his review swrast was ready for it, and the 965 driver is
advertising it already though it has been resulting in many crashes due to
arrays using these defines not being big enough.