net: dl2k: Use proper conversion of dev_addr before IO to device

The driver is using iowriteXX()/ioreadXX() APIs which are LE IO
accessors simplified as

  1. Convert given value _from_ CPU _to_ LE
  2. Write it to the device as is

The dev_addr is a byte stream, but because the driver uses 16-bit
IO accessors, it wants to perform double conversion on BE CPUs,
but it took it wrong, as it effectivelly does two times _from_ CPU
_to_ LE. What it has to do is to consider dev_addr as an array of
LE16 and hence do _from_ LE _to_ CPU conversion, followed by implied
_from_ CPU _to_ LE in the iowrite16().

To achieve that, use get_unaligned_le16(). This will make it correct
and allows to avoid sparse warning as reported by LKP.

Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202312030058.hfZPTXd7-lkp@intel.com/
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20231208153327.3306798-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>