v3dv: set render area for partial clears to match clear rect

While this was already being achieved by the scissort rect set on the
pipeline, we still want to limit the render area to we reduce the tile
coverage of the pass as much as possible and avoid unnecessar
tile load and store operations.

Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/6766>

src/broadcom/vulkan/v3dv_meta_clear.c

@@ -551,8 +551,9 @@ emit_color_clear_rect(struct v3dv_cmd_buffer *cmd_buffer,
          .sType = VK_STRUCTURE_TYPE_RENDER_PASS_BEGIN_INFO,
          .renderPass = pipeline->pass,
          .framebuffer = fb,
-         .renderArea = { .offset = { 0, 0 },
-                         .extent = { fb_info.width, fb_info.height } },
+         .renderArea = {
+            .offset = { rect->rect.offset.x, rect->rect.offset.y },
+            .extent = { rect->rect.extent.width, rect->rect.extent.height } },
          .clearValueCount = 0,
       };