Backported from branch ac2 (commit 85b61097) - CARD_Mount was being called
without CARD_Init first, leaving per-channel control blocks and the DSP
unlock sequence unset. On real Dolphin/hardware this surfaced as a hard
MMIO crash instead of a clean CARD_ERROR_* failure.
Co-Authored-By: Dominic Masters <dominic@domsplace.com>