Kernel: Add GenericInterruptHandler.cpp to aarch64 build

This requires us to add an Interrupts.h file in the Kernel/Arch
directory, which includes the architecture specific files.

The commit also stubs out the functions to be able to compile the
aarch64 Kernel.

Kernel/Arch/aarch64/Dummy.cpp

@@ -8,6 +8,7 @@
 #include <AK/Types.h>
 
 #include <Kernel/FileSystem/Inode.h>
+#include <Kernel/Interrupts/InterruptManagement.h>
 #include <Kernel/KString.h>
 #include <Kernel/Locking/SpinlockProtected.h>
 #include <Kernel/Memory/SharedInodeVMObject.h>
@@ -136,3 +137,13 @@ void KString::operator delete(void*)
 extern "C" {
 FlatPtr kernel_mapping_base;
 }
+
+// InterruptManagement.cpp
+namespace Kernel {
+
+u8 InterruptManagement::acquire_mapped_interrupt_number(u8)
+{
+    VERIFY_NOT_REACHED();
+}
+
+}