comedi: vmk80xx: fix expression for tx buffer size
This is an automated ID intended to aid in discovery of potential security vulnerabilities. The actual impact and attack plausibility have not yet been proven. This ID is fixed in Linux Kernel version v5.15.49 by commit 31ac1cffa76b8996974ef4377cb08c0ccdf92669, it was introduced in version v5.15.2 by commit 06ac746d57e6d32b062e220415c607b7e2e0fa50. For more details please see the references link.