net: Remove KMSG_COMPONENT macro

net: Remove KMSG_COMPONENT macro

The KMSG_COMPONENT macro is a leftover of the s390 specific "kernel message
catalog" from 2008 [1] which never made it upstream.

The macro was added to s390 code to allow for an out-of-tree patch which
used this to generate unique message ids. Also this out-of-tree patch
doesn't exist anymore.

The pattern of how the KMSG_COMPONENT macro is used can also be found at
some non s390 specific code, for whatever reasons. Besides adding an
indirection it is unused.

Remove the macro in order to get rid of a pointless indirection. Replace
all users with the string it defines. In all cases this leads to a simple
replacement like this:

 - #define KMSG_COMPONENT "af_iucv"
 - #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
 + #define pr_fmt(fmt) "af_iucv: " fmt

[1] https://lwn.net/Articles/292650/

Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Acked-by: Alexandra Winter <wintera@linux.ibm.com>
Acked-by: Julian Anastasov <ja@ssi.bg>
Acked-by: Sidraya Jayagond <sidraya@linux.ibm.com>
Link: https://patch.msgid.link/20251126140705.1944278-1-hca@linux.ibm.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>