ALSA: hda - Fix memory leak and error handling in CA0132 DSP loader

This patch fixes a few obvious bugs in DSP loader stuff:
- Fix possible memory leaks in the error path
- Avoid double-free calls in dma_reset()
- Properly set/unset WC bits for DMA buffers
- Add missing error status checks

Signed-off-by: Takashi Iwai <tiwai@suse.de>