default.xml: Bump meta-freertos revision to HEAD of dunfell

This includes some CI updates that are not relevant to us but also
includes a fix[1] that removes an unneeded dependency on yoctobsp.

[1] https://github.com/aehs29/meta-freertos/commit/f3c2edb0f22c34b35a775c5d17ea1424d44bee21



Signed-off-by: Andrei Gherzan <andrei.gherzan@huawei.com>