Fix Clang build and other small fixes (#17736)

1. I fixed the Clang build.
1. I removed what I think is an unnecessary `ptrtoint` in
`rpcs3/Emu/Cell/PPUTranslator.cpp`. I am not 100% sure that it's
correct, but I tested a small LLVM IR snippet and it didn't make a
difference. The ASM code was the same.
1. I also changed the definition of `prefetch_write` from `return
__builtin_prefetch(ptr, 1, 0);` to `return __builtin_prefetch(ptr, 1,
3);` because that's how `_m_prefetchw` is defined in GCC.

Utilities/StrFmt.h

@@ -394,7 +394,7 @@ namespace fmt
 		}
 
 #if !defined(_MSC_VER) || defined(__clang__)
-		[[noreturn]] ~throw_exception();
+		[[noreturn]] ~throw_exception() = default;
 #endif
 	};