s390/qeth: Move all OSA RCs to single enum

s390/qeth: Move all OSA RCs to single enum

OSA Express defines a number of return codes whose meaning is
determined by the issuing command, making them ambiguous. Move
definitions of all return codes including the ambiguous ones to a single
enum block to aid readability and maintainability.

Reviewed-by: Alexandra Winter <wintera@linux.ibm.com>
Signed-off-by: Aswin Karuvally <aswin@linux.ibm.com>
Link: https://patch.msgid.link/20251113144209.2140061-2-aswin@linux.ibm.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>