edk2: update submodule to edk2-stable202408.01

Updates the subhook submodule to point to a edk2 mirror repo.
Fixes recursive cloning of the edk2 submodule.

Cc: Peter Maydell <[email protected]>
Resolves: https://gitlab.com/qemu-project/qemu/-/issues/2660
Signed-off-by: Gerd Hoffmann <[email protected]>
Signed-off-by: Dario Faggioli <[email protected]>