s390/net: Remove LCS driver

s390/net: Remove LCS driver

The original Open Systems Adapter (OSA) was introduced by IBM in the
mid-90s. These were then superseded by OSA-Express in 1999 which used
Queued Direct IO to greatly improve throughput. The newer cards
retained the older, slower non-QDIO (OSE) modes for compatibility with
older systems. In Linux, the lcs driver was responsible for cards
operating in the older OSE mode and the qeth driver was introduced to
allow the OSA-Express cards to operate in the newer QDIO (OSD) mode.

For an S390 machine from 1998 or later, there is no reason to use the
OSE mode and lcs driver as all OSA cards since 1999 provide the faster
OSD mode. As a result, it's been years since we have heard of a
customer configuration involving the lcs driver.

This patch removes the lcs driver. The technology it supports has been
obsolete for past 25+ years and is irrelevant for current use cases.

Reviewed-by: Alexandra Winter <wintera@linux.ibm.com>
Acked-by: Heiko Carstens <hca@linux.ibm.com>
Acked-by: Peter Oberparleiter <oberpar@linux.ibm.com>
Signed-off-by: Aswin Karuvally <aswin@linux.ibm.com>
Signed-off-by: Alexandra Winter <wintera@linux.ibm.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Link: https://patch.msgid.link/20250204103135.1619097-1-wintera@linux.ibm.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>