Use system nanobind instead of fetching it
--- a/tensilelite/rocisa/CMakeLists.txt
+++ b/tensilelite/rocisa/CMakeLists.txt
@@ -61,13 +61,7 @@ if(HIPBLASLT_BUNDLE_PYTHON_DEPS OR ROCISA_STANDALONE)
         endif()
         find_package(nanobind REQUIRED CONFIG)
     else()
-        include(FetchContent)
-        FetchContent_Declare(
-          nanobind
-          GIT_REPOSITORY https://github.com/wjakob/nanobind.git
-          GIT_TAG        9b3afa9dbdc23641daf26fadef7743e7127ff92f # v2.6.1
-        )
-        FetchContent_MakeAvailable(nanobind)
+        find_package(nanobind CONFIG REQUIRED)
         if(ROCISA_USE_STABLE_ABI)
             find_package(Python 3.12 COMPONENTS Interpreter Development.Module Development.SABIModule REQUIRED)
         endif()