ALSA: intel8x0: Fix missing check in snd_intel8x0m_create

When device_type == DEVICE_ALI, we should also check the return
value of pci_iomap() to avoid potential null pointer dereference.

Signed-off-by: Dinghao Liu <dinghao.liu@zju.edu.cn>
Link: https://lore.kernel.org/r/20210131100916.7915-1-dinghao.liu@zju.edu.cn
Signed-off-by: Takashi Iwai <tiwai@suse.de>