trivial: Silence a warning

Something that was created was not referenced, which caused a
lint, which fails CI.  This trivial change just references the
thing that was created but previously unreferenced.

Signed-off-by: Dan Cross <cross@gajendra.net>

theon/src/main.rs

@@ -140,7 +140,7 @@ const BINARY_LOAD_REGION_END: HPA = load_addr(BINARY_TABLE.len());
 #[cfg_attr(not(test), no_mangle)]
 pub extern "C" fn main(mbinfo_phys: u64) -> ! {
     arch::lapic::enable_x2apic();
-    let multiboot = x86_64::pc::init::start(mbinfo_phys);
+    let multiboot = x86_64::platform::init::start(mbinfo_phys);
     let crate::x86_64::pc::multiboot1::InitInfo { memory_regions, regions, modules } =
         multiboot.info();
     assert!(theon_fits(&regions));