ALSA: ctxfi: cthw20k2: fix mask on conf to allow 4 bits

stable inclusion
from stable-5.10.22
commit 253b7a11ce26d30f375fb8b7d51e988bc2dc9cd0
bugzilla: 50796

--------------------------------

[ Upstream commit 26a9630c ]

Currently the mask operation on variable conf is just 3 bits so
the switch statement case value of 8 is unreachable dead code.
The function daio_mgr_dao_init can be passed a 4 bit value,
function dao_rsc_init calls it with conf set to:

     conf = (desc->msr & 0x7) | (desc->passthru << 3);

so clearly when desc->passthru is set to 1 then conf can be
at least 8.

Fix this by changing the mask to 0xf.

Fixes: 8cc72361 ("ALSA: SB X-Fi driver merge")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Link: https://lore.kernel.org/r/20210227001527.1077484-1-colin.king@canonical.com


Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Chen Jun <chenjun102@huawei.com>
Acked-by:   Weilong Chen <chenweilong@huawei.com>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>