A bit more GetPointer cleanup.

Probably not worth it for performance reasons, but some semantic cleanup
is good, especially the accidental GetPointer -> writable casts without
using GetPointerWrite.

Using Unchecked on already checked pointers, or when we'd crash anyway
if it returned nullptr, is good for clarity.

Core/TextureReplacer.cpp

@@ -402,7 +402,7 @@ u32 TextureReplacer::ComputeHash(u32 addr, int bufw, int w, int h, GETextureForm
 		}
 	}
 
-	const u8 *checkp = Memory::GetPointer(addr);
+	const u8 *checkp = Memory::GetPointerUnchecked(addr);
 	if (reduceHash_) {
 		reduceHashSize = LookupReduceHashRange(w, h);
 		// default to reduceHashGlobalValue which default is 0.5