lang/silq: remove llvm10 dependency
This was added in 4949e8270ef54e5ae32f1ab66585ca0b55fc6235 to work
around an issue when linking with LLVM 13's lld when LDC was not also
using LLVM 13. LDC now uses LLVM 15 and and silq builds fine without
this patch.
PR: 273977
Approved by: maintainer timeout