IOWin: Make error 0x1F less noisy.

This error code is used by third-party WiiMote adapters to signal the
absence of a WiiMote connected to their virtual HID port. Ignoring it
removes some log spamming and doesn't change anything in terms of
behavior.
IOWin: rework _IOWrite OVERLAPPED/bytes written handling.

CheckDeviceType_Write uses an OVERLAPPED structure to make sure some bytes
were written to the device for a given _IOWrite operation. However, the
OVERLAPPED structure is only used for the BlueSoleil stack, not the MS stack
(which goes through an alternate HID path instead of WriteFile, and does not
have an equivalent async operation).

Make _IOWrite return the number of written bytes instead, since it knows
about the Bluetooth stack being used.
Merge pull request #661 from delroth/dolphinbar

Fix WiiMote issues causing DolphinBar to not work