watchdog: diag288_wdt: Remove KMSG_COMPONENT macro

watchdog: diag288_wdt: 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 doesn't
exist anymore.

Remove the macro in order to get rid of a pointless indirection.

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

Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>