lockdep: Move list.h inclusion into lockdep.h

Currently lockdep_types.h includes list.h without actually using any
of its macros or functions.  All it needs are the type definitions
which were moved into types.h long ago.  This potentially causes
inclusion loops because both are included by many core header
files.

This patch moves the list.h inclusion into lockdep.h.  Note that
we could probably remove it completely but that could potentially
result in compile failures should any end users not include list.h
directly and also be unlucky enough to not get list.h via some other
header file.
Reported-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Petr Mladek <pmladek@suse.com>
Link: https://lkml.kernel.org/r/20200716063649.GA23065@gondor.apana.org.au

include/linux/lockdep.h

@@ -21,6 +21,7 @@ extern int lock_stat;
 #ifdef CONFIG_LOCKDEP
 
 #include <linux/linkage.h>
+#include <linux/list.h>
 #include <linux/debug_locks.h>
 #include <linux/stacktrace.h>
 

include/linux/lockdep_types.h

@@ -32,8 +32,6 @@ enum lockdep_wait_type {
 
 #ifdef CONFIG_LOCKDEP
 
-#include <linux/list.h>
-
 /*
  * We'd rather not expose kernel/lockdep_states.h this wide, but we do need
  * the total number of states... :-(