libSceHmdSetupDialog technical debt

libSceHmdSetupDialog - the HMD setup dialog runs the common-dialog state machine but shows nothing and reports the user as having cancelled, as no headset is supported (see libSceHmd2). The signatures are from Orbital's type database; the result layout beyond the leading int32_t result code is not known, so nothing else is written. Returning 0x80B8000D for an unwritable result pointer is a host-safety fallback with console behavior unmeasured.