This function does *not* always convert from UTF-16. It converts
from UTF-16 on Windows and UTF-32 on other operating systems.
Also renaming UTF8ToUTF16 for consistency, even though it
technically doesn't have the same problem since it only was
implemented on Windows.
It appears that some older drivers do not support
CreateSwapChainForHwnd, resulting in DXGI_ERROR_INVALID_CALL. For these
cases, fall back to the base CreateSwapChain() from DXGI 1.0.
In theory this should also let us run on Win7 without the platform
update, but in reality we require the newer shader compiler so this
probably won't work regardless. Also any hardware of this vintage is
unlikely to run Dolphin well.
JosJuice