bug: Provide dummy version of bug_get_file_line() when !GENERIC_BUG

Provide the missing dummy bug_get_file_line() implementation when
GENENERIC_BUG isn't selected.

Reported-by: kernel test robot <lkp@intel.com>
Fixes: 26dbc7e299 ("bug: Factor out a getter for a bug's file line")
Cc: Andrew Scull <ascull@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>

include/linux/bug.h

@@ -61,6 +61,13 @@ static inline enum bug_trap_type report_bug(unsigned long bug_addr,
 	return BUG_TRAP_TYPE_BUG;
 }
 
+struct bug_entry;
+static inline void bug_get_file_line(struct bug_entry *bug, const char **file,
+				     unsigned int *line)
+{
+	*file = NULL;
+	*line = 0;
+}
 
 static inline void generic_bug_clear_once(void) {}