kernel/shared_memory: Get rid of the use of global accessor functions within Create()

Given we already pass in a reference to the kernel that the shared
memory instance is created under, we can just use that to check the
current process, rather than using the global accessor functions.

This allows removing direct dependency on the system instance entirely.

src/core/hle/kernel/shared_memory.cpp

@@ -6,7 +6,6 @@
 
 #include "common/assert.h"
 #include "common/logging/log.h"
-#include "core/core.h"
 #include "core/hle/kernel/errors.h"
 #include "core/hle/kernel/kernel.h"
 #include "core/hle/kernel/shared_memory.h"
@@ -34,8 +33,8 @@ SharedPtr<SharedMemory> SharedMemory::Create(KernelCore& kernel, Process* owner_
         shared_memory->backing_block_offset = 0;
 
         // Refresh the address mappings for the current process.
-        if (Core::CurrentProcess() != nullptr) {
-            Core::CurrentProcess()->VMManager().RefreshMemoryBlockMappings(
+        if (kernel.CurrentProcess() != nullptr) {
+            kernel.CurrentProcess()->VMManager().RefreshMemoryBlockMappings(
                 shared_memory->backing_block.get());
         }
     } else {