Input: ims-pcu - fix potential infinite loop in CDC union descriptor parsing

In the Linux kernel, the following vulnerability has been resolved: Input: ims-pcu - fix potential infinite loop in CDC union descriptor parsing The driver parses CDC union descriptors in ims_pcu_get_cdc_union_desc() by iterating through the extra descriptor data. However, it does not verify that the bLength of each descriptor is at least 2. A malicious device could provide a descriptor with bLength = 0, leading to an infinite loop in the driver. Add a check to ensure bLength is at least 2 before proceeding with parsing.