MemoryPatches: In-class initialize is_enabled state for MemoryPatch instances

Given this is what occurs in both constructors (as one just passes
through to another), we can just initialize the member directly.

While we're at it, amend the struct to follow the general ordering
convention of:

<new types>
<functions>
<variables>

Source/Core/Common/Debug/MemoryPatches.cpp

@@ -11,7 +11,7 @@
 namespace Common::Debug
 {
 MemoryPatch::MemoryPatch(u32 address_, std::vector<u8> value_)
-    : address(address_), value(std::move(value_)), is_enabled(State::Enabled)
+    : address(address_), value(std::move(value_))
 {
 }