lib: packing: remove kernel-doc from header file

It is not necessary to have the kernel-doc duplicated both in the
header and in the implementation. It is better to have it near the
implementation of the function, since in C, a function can have N
declarations, but only one definition.

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: Jacob Keller <jacob.e.keller@intel.com>
Reviewed-by: Przemek Kitszel <przemyslaw.kitszel@intel.com>
Reviewed-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Link: https://patch.msgid.link/20241002-packing-kunit-tests-and-split-pack-unpack-v2-3-8373e551eae3@intel.com


Signed-off-by: Jakub Kicinski <kuba@kernel.org>