st/dri: Allow creating OpenGL 3.3 core contexts

Enables OpenGL 3.3 piglit tests.

Reviewed-by: Marek Olšák <marek.olsak@amd.com>

src/gallium/state_trackers/dri/common/dri_screen.c

@@ -455,7 +455,7 @@ dri_init_screen_helper(struct dri_screen *screen,
    if (screen->st_api->profile_mask & ST_PROFILE_DEFAULT_MASK)
       screen->sPriv->max_gl_compat_version = 30;
    if (screen->st_api->profile_mask & ST_PROFILE_OPENGL_CORE_MASK)
-      screen->sPriv->max_gl_core_version = 32;
+      screen->sPriv->max_gl_core_version = 33;
    if (screen->st_api->profile_mask & ST_PROFILE_OPENGL_ES1_MASK)
       screen->sPriv->max_gl_es1_version = 11;
    if (screen->st_api->profile_mask & ST_PROFILE_OPENGL_ES2_MASK)