arch: x86 -> x86_64 and build system changes

arch/x86/kernel/Makefile.arch

@@ -1,7 +0,0 @@
-IHK_OBJS += cpu.o interrupt.o memory.o trampoline.o local.o context.o
-IHK_OBJS += perfctr.o syscall.o vsyscall.o
-# POSTK_DEBUG_ARCH_DEP_18 coredump arch separation.
-# IHK_OBJS added coredump.o
-ifeq ($(ARCH), arm64)
-IHK_OBJS += coredump.o
-endif

arch/x86_64/kernel/Makefile.arch.in

@@ -0,0 +1,2 @@
+IHK_OBJS += cpu.o interrupt.o memory.o trampoline.o local.o context.o
+IHK_OBJS += perfctr.o syscall.o vsyscall.o