cassini: Fix a memory leak in the error handling path of cas_init_one()

In the Linux kernel, the following vulnerability has been resolved: cassini: Fix a memory leak in the error handling path of cas_init_one() cas_saturn_firmware_init() allocates some memory using vmalloc(). This memory is freed in the .remove() function but not it the error handling path of the probe. Add the missing vfree() to avoid a memory leak, should an error occur.