crypto: caam - fix DMA corruption on long hmac keys

In the Linux kernel, the following vulnerability has been resolved: crypto: caam - fix DMA corruption on long hmac keys When a key longer than block size is supplied, it is copied and then hashed into the real key. The memory allocated for the copy needs to be rounded to DMA cache alignment, as otherwise the hashed key may corrupt neighbouring memory. The rounding was performed, but never actually used for the allocation. Fix this by replacing kmemdup with kmalloc for a larger buffer, followed by memcpy.