mesa: Introduce a compiler enum for tessellation spacing.

It feels weird using GL_* enums in a Vulkan driver.

v2: Fix the TESS_SPACING -> PIPE_TESS_SPACING conversion.

Signed-off-by: Kenneth Graunke <kenneth@whitecape.org>
Reviewed-by: Timothy Arceri <timothy.arceri@collabora.com>
Reviewed-by: Jason Ekstrand <jason@jlekstrand.net>

src/compiler/shader_info.h

@@ -149,7 +149,7 @@ typedef struct shader_info {
 
       struct {
          uint32_t primitive_mode; /* GL_TRIANGLES, GL_QUADS or GL_ISOLINES */
-         uint32_t spacing;        /* GL_EQUAL, GL_FRACTIONAL_EVEN, GL_FRACTIONAL_ODD */
+         enum gl_tess_spacing spacing;
          /** Is the vertex order counterclockwise? */
          bool ccw;
          bool point_mode;