refactor(port_arm): use #![feature(generic_arg_infer)]

Author: yvt

src/r3_port_arm/src/lib.rs

@@ -1,5 +1,6 @@
 #![feature(const_ptr_offset_from)]
 #![feature(const_refs_to_cell)]
+#![feature(generic_arg_infer)]
 #![feature(const_trait_impl)]
 #![feature(naked_functions)]
 #![feature(const_mut_refs)]

src/r3_port_arm/src/startup/imp.rs

@@ -15,7 +15,7 @@ impl VectorTable {
         Self {
             // trampolines[N]:
             //      ldr pc, [pc, #24]   ; targets + N * 4
-            _trampolines: [0xe59ff018; 8],
+            _trampolines: [0xe59ff018; _],
             // trampolines[N]
             _targets: [
                 unhandled_exception_handler,