mctp: remove MODULE_LICENSE in non-modules

Since commit 8b41fc4 ("kbuild: create modules.builtin without
Makefile.modbuiltin or tristate.conf"), MODULE_LICENSE declarations
are used to identify modules. As a consequence, uses of the macro
in non-modules will cause modprobe to misidentify their containing
object file as a module when it is not (false positives), and modprobe
might succeed rather than failing with a suitable error message.

So remove it in the files in this commit, none of which can be built as
modules.

Signed-off-by: Nick Alcock <nick.alcock@oracle.com>
Suggested-by: Luis Chamberlain <mcgrof@kernel.org>
Cc: Hitomi Hasegawa <hasegawa-hitomi@fujitsu.com>
Cc: Jeremy Kerr <jk@codeconstruct.com.au>
Cc: Matt Johnston <matt@codeconstruct.com.au>
Link: https://lore.kernel.org/r/20230308121230.5354-2-nick.alcock@oracle.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

net/mctp/af_mctp.c

@@ -704,7 +704,6 @@ subsys_initcall(mctp_init);
 module_exit(mctp_exit);
 
 MODULE_DESCRIPTION("MCTP core");
-MODULE_LICENSE("GPL v2");
 MODULE_AUTHOR("Jeremy Kerr <jk@codeconstruct.com.au>");
 
 MODULE_ALIAS_NETPROTO(PF_MCTP);