[LLVM][NFC] Ignore including the GNUInstallDirs on the GPU (#83910)

Summary:
I've begun treating GPU runtimes builds as cross-compiling with the LLVM
infrastructure. However, we include a lot of random stuff that the GPU
build isn't prepared to handle. This currently emits a warning, and
while it's not striclty necessary, is annoying. This patch suppresses it
by not including the standard GNU install directory resources when used
from the GPU.