[kernel] Get rid of page_manager

page_manager is dead - final uses replaced in vm_space (page_in and
clear). Removed the header and cpp, and other lingering references.

src/kernel/objects/endpoint.cpp

@@ -1,7 +1,6 @@
 #include "objects/endpoint.h"
 #include "objects/process.h"
 #include "objects/thread.h"
-#include "page_manager.h"
 #include "scheduler.h"
 #include "vm_space.h"
 
@@ -87,7 +86,6 @@ endpoint::do_message_copy(const endpoint::thread_data &sender, endpoint::thread_
 	if (sender.len > *receiver.len_p)
 		return j6_err_insufficient;
 
-	page_manager *pm = page_manager::get();
 	vm_space &source = sender.th->parent().space();
 	vm_space &dest = receiver.th->parent().space();
 	vm_space::copy(source, dest, sender.data, receiver.data, sender.len);

src/kernel/objects/process.cpp

@@ -4,7 +4,6 @@
 #include "cpu.h"
 #include "objects/process.h"
 #include "objects/thread.h"
-#include "page_manager.h"
 
 // This object is initialized _before_ global constructors are called,
 // so we don't want it to have a global constructor at all, lest it

src/kernel/objects/vm_area.cpp

@@ -51,7 +51,7 @@ vm_area::remove_from(vm_space *space)
 	if (space && base) {
 		for (auto &m : m_mappings)
 			if (m.state == state::mapped)
-				space->page_out(*base + m.offset, m.count);
+				space->clear(*base + m.offset, m.count);
 		m_procs.erase(space);
 	}
 	return j6_status_ok;
@@ -272,7 +272,7 @@ vm_area::unmap(uintptr_t offset, size_t count)
 	for (auto &it : m_procs) {
 		uintptr_t addr = it.val + offset;
 		vm_space *space = it.key;
-		space->page_out(addr, count);
+		space->clear(addr, count);
 	}
 }