kdb: break out of kdb_ll() when command is terminated

Without this patch the "ll" linked-list traversal command won't
terminate when you hit q/Q.

Signed-off-by: Martin Hicks <[e-mail]>
Signed-off-by: Jason Wessel <[e-mail]>

kernel/debug/kdb/kdb_main.c

···
 	while (va) {
 		char buf[80];
 
+		if (KDB_FLAG(CMD_INTERRUPT))
+			return 0;
+
 		sprintf(buf, "%s " kdb_machreg_fmt "\n", command, va);
 		diag = kdb_parse(buf);
 		if (diag)