modpost: add handler function pointer to sectioncheck.

This will be useful when we want to have special handlers which need to go
through more hops to print useful information to the user.

Signed-off-by: Quentin Casasnovas <quentin.casasnovas@oracle.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
1 file changed