Memory: Move address type conversion routines to memory.cpp/h

These helpers aren't really part of the kernel, and mem_map.cpp/h is
going to be moved there next.

src/core/hle/kernel/resource_limit.cpp

@@ -6,7 +6,6 @@
 
 #include "common/logging/log.h"
 
-#include "core/mem_map.h"
 #include "core/hle/kernel/resource_limit.h"
 
 namespace Kernel {

src/core/hle/service/gsp_gpu.cpp

@@ -4,7 +4,6 @@
 
 #include "common/bit_field.h"
 
-#include "core/mem_map.h"
 #include "core/memory.h"
 #include "core/hle/kernel/event.h"
 #include "core/hle/kernel/shared_memory.h"

src/core/hle/service/y2r_u.cpp

@@ -10,7 +10,6 @@
 #include "core/hle/kernel/event.h"
 #include "core/hle/service/y2r_u.h"
 #include "core/hw/y2r.h"
-#include "core/mem_map.h"
 
 #include "video_core/renderer_base.h"
 #include "video_core/utils.h"