net: phy: aquantia: fix commenting format

Comment was erroneously added with /**, amend this to use /* as it is
not a kernel-doc.

Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202504262247.1UBrDBVN-lkp@intel.com/


Signed-off-by: Aryan Srivastava <aryan.srivastava@alliedtelesis.co.nz>
Reviewed-by: Simon Horman <horms@kernel.org>
Link: https://patch.msgid.link/20250428214920.813038-1-aryan.srivastava@alliedtelesis.co.nz


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