ibmvnic: Use kernel helpers for hex dumps

In the Linux kernel, the following vulnerability has been resolved: ibmvnic: Use kernel helpers for hex dumps Previously, when the driver was printing hex dumps, the buffer was cast to an 8 byte long and printed using string formatters. If the buffer size was not a multiple of 8 then a read buffer overflow was possible. Therefore, create a new ibmvnic function that loops over a buffer and calls hex_dump_to_buffer instead. This patch address KASAN reports like the one below: ibmvnic 30000003 env3: Login Buffer: ibmvnic 30000003 env3: 01000000af000000 <...> ibmvnic 30000003 env3: 2e6d62692e736261 ibmvnic 30000003 env3: 65050003006d6f63 ================================================================== BUG: KASAN: slab-out-of-bounds in ibmvnic_login+0xacc/0xffc [ibmvnic] Read of size 8 at addr c0000001331a9aa8 by task ip/17681 <...> Allocated by task 17681: <...> ibmvnic_login+0x2f0/0xffc [ibmvnic] ibmvnic_open+0x148/0x308 [ibmvnic] __dev_open+0x1ac/0x304 <...> The buggy address is located 168 bytes inside of allocated 175-byte region [c0000001331a9a00, c0000001331a9aaf) <...> ================================================================= ibmvnic 30000003 env3: 000000000033766e