ALSA: portman2x4: Use bitwise instead of arithmetic operator for flags

Fix the following coccinelle warning:

sound/drivers/portman2x4.c:460:34-35: WARNING: sum of probable bitmasks, consider |

Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Samuel Zou <zou_wei@huawei.com>
Link: https://lore.kernel.org/r/1588834135-14842-1-git-send-email-zou_wei@huawei.com


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