CVE-2026-64145: wifi: wilc1000: fix dma_buffer leak on bus acquire failure

In the Linux kernel, the following vulnerability has been resolved:

wifi: wilc1000: fix dmabuffer leak on bus acquire failure

wilcwlanfirmwaredownload() allocates dmabuffer with kmalloc() at the top of the function and uses a 'fail:' label to free it via kfree(dmabuffer) on error.

All later error paths correctly use 'goto fail' to route through this cleanup. However, the early failure path after the first acquirebus() call uses a bare 'return ret;', which leaks dmabuffer whenever the bus acquire fails.

Replace the early return with goto fail so the existing cleanup path runs.

Found via a custom Coccinelle semantic patch hunting for kmalloc'd locals leaked on early-return error paths in driver firmware-download code.