These syncs have the goal to transfer host filesystem changes to the VM,
but they have no effect because 1) syncing in the VM can't possibly pull
in host data and 2) 9p is accessing the host filesystem on the cached
layer anyways, so even syncing on the host would have no effect in the
VM.

xchg is advertised as a bidirectional exchange dir, but file content
transfer from host to VM fails due to caching:
If a file is read in the VM and then modified on the host, subsequent
re-reads in the VM can yield old, cached data.
This is caused by the use of 9p's cache=loose mode that is explicitly
meant for read-only mounts.

9p doesn't provide any suitable cache modes, so fix this by disabling
caching.

Also, remove a now unnecessary sync in the test driver.

fix inconsistent caching of VM xchg dirs

iconpack-obsidian: 4.11 -> 4.12

lxqt.lxqt-qtplugin: 0.15.0 -> 0.15.1

Without it, building a document fails with the following error:

pdflatex failed
index.tex: File `pdflscape.sty' not found.
index.tex:47: Emergency stop.

u-boot: Add ROC-PC-RK3399 build

zsh-powerlevel10k: v1.7.0 -> v1.11.0

v2ray: 4.23.2 -> 4.23.3

mdcat: 0.17.1 -> 0.18.2