glsl: fix check SSBOs support for builtin functions

has_shader_storage_buffer_objects() returns true also if the OpenGL
context is 4.30 or ES 3.1.

Previously, we were saying that all atomic*() GLSL builtin functions
for SSBOs were not available when OpenGL ES 3.1 context was in use.

Fixes 48 dEQP-GLES31 tests:

dEQP-GLES31.functional.ssbo.atomic.*

Signed-off-by: Samuel Iglesias Gonsalvez <siglesias@igalia.com>
Reviewed-by: Tapani Pälli <tapani.palli@intel.com>
Reviewed-by: Iago Toral Quiroga <itoral@igalia.com>

src/glsl/builtin_functions.cpp

@@ -403,7 +403,7 @@ shader_atomic_counters(const _mesa_glsl_parse_state *state)
 static bool
 shader_storage_buffer_object(const _mesa_glsl_parse_state *state)
 {
-   return state->ARB_shader_storage_buffer_object_enable;
+   return state->has_shader_storage_buffer_objects();
 }
 
 static bool