i965/gen7: fix encoding of (huge) surface size for BRW_SURFACE_BUFFER
i965/gen7: fix encoding of (huge) surface size for BRW_SURFACE_BUFFER

Unlike GEN6, the bits of entry count are distributed like this

  width  = (entry_count & 0x0000007f);       /* bits [6:0] */
  height = (entry_count & 0x001fff80) >> 7;  /* bits [20:7] */
  depth  = (entry_count & 0x7fe00000) >> 21; /* bits [30:21] */

The maximum entry count is still limited to 2^27.

This was noted while going over the PRM.  No test is impacted, because
1<<20 (the bit that moved) is much larger than GL_UNIFORM_BLOCK_MAX_SIZE,
GL_MAX_TEXTURE_BUFFER_SIZE, or MAX_*_UNIFORM_COMPONENTS.

v2: Explain more in the commit message (by anholt)

Reviewed-by: Eric Anholt <96f164ad4d9b2b0dacf8ebee2bb1eeb3aa69adf1@anholt.net>

bkaradzic/glsl-optimizer,metora/MesaGLSLCompiler,metora/MesaGLSLCompiler,djreep81/glsl-optimizer,tokyovigilante/glsl-optimizer,mcanthony/glsl-optimizer,djreep81/glsl-optimizer,benaadams/glsl-optimizer,mapbox/glsl-optimizer,benaadams/glsl-optimizer,wolf96/glsl-optimizer,bkaradzic/glsl-optimizer,wolf96/glsl-optimizer,zeux/glsl-optimizer,mapbox/glsl-optimizer,bkaradzic/glsl-optimizer,zz85/glsl-optimizer,benaadams/glsl-optimizer,mcanthony/glsl-optimizer,jbarczak/glsl-optimizer,tokyovigilante/glsl-optimizer,jbarczak/glsl-optimizer,benaadams/glsl-optimizer,metora/MesaGLSLCompiler,dellis1972/glsl-optimizer,zz85/glsl-optimizer,zz85/glsl-optimizer,zeux/glsl-optimizer,zeux/glsl-optimizer,wolf96/glsl-optimizer,zz85/glsl-optimizer,zz85/glsl-optimizer,mapbox/glsl-optimizer,dellis1972/glsl-optimizer,mcanthony/glsl-optimizer,zz85/glsl-optimizer,mcanthony/glsl-optimizer,jbarczak/glsl-optimizer,zeux/glsl-optimizer,djreep81/glsl-optimizer,bkaradzic/glsl-optimizer,jbarczak/glsl-optimizer,dellis1972/glsl-optimizer,wolf96/glsl-optimizer,dellis1972/glsl-optimizer,djreep81/glsl-optimizer,wolf96/glsl-optimizer,mapbox/glsl-optimizer,tokyovigilante/glsl-optimizer,benaadams/glsl-optimizer,tokyovigilante/glsl-optimizer,mapbox/glsl-optimizer,djreep81/glsl-optimizer,dellis1972/glsl-optimizer,tokyovigilante/glsl-optimizer,bkaradzic/glsl-optimizer,jbarczak/glsl-optimizer,mcanthony/glsl-optimizer,benaadams/glsl-optimizer,zeux/glsl-optimizer