filesystem: Remove pragma disabling global optimizations

This was just an artifact missed during PR review.

src/core/hle/service/filesystem/filesystem.cpp

@@ -2,8 +2,6 @@
 // Licensed under GPLv2 or any later version
 // Refer to the license.txt file included.
 
-#pragma optimize("", off)
-
 #include "common/assert.h"
 #include "common/file_util.h"
 #include "core/core.h"