llm: update llama.cpp submodule to `7c26775`

llm/llama.cpp

@@ -1 +1 @@
-Subproject commit 5921b8f089d3b7bda86aac5a66825df6a6c10603
+Subproject commit 7c26775adb579e92b59c82e8084c07a1d0f75e9c