ALSA: firewire-lib: fix check for the size of isochronous packet payload

stable inclusion
from stable-5.10.40
commit 78a37c03c65c0853286c63da72288da0703629b3
bugzilla: 51882
CVE: NA

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

commit 395f41e2 upstream.

The check for size of isochronous packet payload just cares of the size of
IR context payload without the size of CIP header.

Cc: <stable@vger.kernel.org>
Fixes: f11453c7 ("ALSA: firewire-lib: use 16 bytes IR context header to separate CIP header")
Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Link: https://lore.kernel.org/r/20210513125652.110249-4-o-takashi@sakamocchi.jp


Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Chen Jun <chenjun102@huawei.com>
Acked-by: Weilong Chen <chenweilong@huawei.com>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>