mesa: Implement TEXTURE_IMMUTABLE_LEVELS for ES 3.0.

NOTE: This is a candidate for the 9.1 branch.
Fixes piglit's texture-immutable-levels test.
Reported-by: Marek Olšák <maraeo@gmail.com>
Reviewed-by: Brian Paul <brianp@vmware.com>
diff --git a/src/mesa/main/mtypes.h b/src/mesa/main/mtypes.h
index 8c38aa7..a0e7e28 100644
--- a/src/mesa/main/mtypes.h
+++ b/src/mesa/main/mtypes.h
@@ -1179,6 +1179,7 @@
    GLfloat Priority;		/**< in [0,1] */
    GLint BaseLevel;		/**< min mipmap level, OpenGL 1.2 */
    GLint MaxLevel;		/**< max mipmap level, OpenGL 1.2 */
+   GLint ImmutableLevels;       /**< ES 3.0 / ARB_texture_view */
    GLint _MaxLevel;		/**< actual max mipmap level (q in the spec) */
    GLfloat _MaxLambda;		/**< = _MaxLevel - BaseLevel (q - b in spec) */
    GLint CropRect[4];           /**< GL_OES_draw_texture */
diff --git a/src/mesa/main/texparam.c b/src/mesa/main/texparam.c
index 120845b..bd2f751 100644
--- a/src/mesa/main/texparam.c
+++ b/src/mesa/main/texparam.c
@@ -1460,6 +1460,12 @@
          *params = (GLfloat) obj->Immutable;
          break;
 
+      case GL_TEXTURE_IMMUTABLE_LEVELS:
+         if (!_mesa_is_gles3(ctx))
+            goto invalid_pname;
+         *params = (GLfloat) obj->ImmutableLevels;
+         break;
+
       case GL_REQUIRED_TEXTURE_IMAGE_UNITS_OES:
          if (!_mesa_is_gles(ctx) || !ctx->Extensions.OES_EGL_image_external)
             goto invalid_pname;
@@ -1637,6 +1643,12 @@
          *params = (GLint) obj->Immutable;
          break;
 
+      case GL_TEXTURE_IMMUTABLE_LEVELS:
+         if (!_mesa_is_gles3(ctx))
+            goto invalid_pname;
+         *params = obj->ImmutableLevels;
+         break;
+
       case GL_REQUIRED_TEXTURE_IMAGE_UNITS_OES:
          if (!_mesa_is_gles(ctx) || !ctx->Extensions.OES_EGL_image_external)
             goto invalid_pname;
diff --git a/src/mesa/main/texstorage.c b/src/mesa/main/texstorage.c
index 00f19ba..675fd74 100644
--- a/src/mesa/main/texstorage.c
+++ b/src/mesa/main/texstorage.c
@@ -397,6 +397,7 @@
       }
 
       texObj->Immutable = GL_TRUE;
+      texObj->ImmutableLevels = levels;
    }
 }