refactor(adapter): split trap/page_table/smp/entry by concern; trim comments

crates/adapter-riscv/src/devices/mod.rs

@@ -1,8 +1,4 @@
-// What boot still sets up for userspace, all through the kernel's mapping
-// API: the display's page quota and the BootInfo page that tells init
-// where its device capabilities are. Drivers set up their own devices
-// with the capabilities init hands them; processes share memory through
-// regions they create.
+// Boot-time userspace setup: the display's page quota and init's BootInfo page.
 
 use crate::hw::uart::Uart;
 use types::address::VirtualAddress;