f2fs: fix sparse warnings

This patch resolves the following warnings.

include/trace/events/f2fs.h:150:1: warning: expression using sizeof bool
include/trace/events/f2fs.h:180:1: warning: expression using sizeof bool
include/trace/events/f2fs.h:990:1: warning: expression using sizeof bool
include/trace/events/f2fs.h:990:1: warning: expression using sizeof bool
include/trace/events/f2fs.h:150:1: warning: odd constant _Bool cast (ffffffffffffffff becomes 1)
include/trace/events/f2fs.h:180:1: warning: odd constant _Bool cast (ffffffffffffffff becomes 1)
include/trace/events/f2fs.h:990:1: warning: odd constant _Bool cast (ffffffffffffffff becomes 1)
include/trace/events/f2fs.h:990:1: warning: odd constant _Bool cast (ffffffffffffffff becomes 1)

fs/f2fs/checkpoint.c:27:19: warning: symbol 'inode_entry_slab' was not declared. Should it be static?
fs/f2fs/checkpoint.c:577:15: warning: cast to restricted __le32
fs/f2fs/checkpoint.c:592:15: warning: cast to restricted __le32

fs/f2fs/trace.c:19:1: warning: symbol 'pids' was not declared. Should it be static?
fs/f2fs/trace.c:21:21: warning: symbol 'last_io' was not declared. Should it be static?

Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
diff --git a/include/trace/events/f2fs.h b/include/trace/events/f2fs.h
index 6962982..5422dbf 100644
--- a/include/trace/events/f2fs.h
+++ b/include/trace/events/f2fs.h
@@ -149,14 +149,14 @@
 
 TRACE_EVENT(f2fs_sync_file_exit,
 
-	TP_PROTO(struct inode *inode, bool need_cp, int datasync, int ret),
+	TP_PROTO(struct inode *inode, int need_cp, int datasync, int ret),
 
 	TP_ARGS(inode, need_cp, datasync, ret),
 
 	TP_STRUCT__entry(
 		__field(dev_t,	dev)
 		__field(ino_t,	ino)
-		__field(bool,	need_cp)
+		__field(int,	need_cp)
 		__field(int,	datasync)
 		__field(int,	ret)
 	),
@@ -185,7 +185,7 @@
 
 	TP_STRUCT__entry(
 		__field(dev_t,	dev)
-		__field(bool,	dirty)
+		__field(int,	dirty)
 		__field(int,	wait)
 	),
 
@@ -989,14 +989,15 @@
 
 TRACE_EVENT(f2fs_issue_flush,
 
-	TP_PROTO(struct super_block *sb, bool nobarrier, bool flush_merge),
+	TP_PROTO(struct super_block *sb, unsigned int nobarrier,
+					unsigned int flush_merge),
 
 	TP_ARGS(sb, nobarrier, flush_merge),
 
 	TP_STRUCT__entry(
 		__field(dev_t,	dev)
-		__field(bool, nobarrier)
-		__field(bool, flush_merge)
+		__field(unsigned int, nobarrier)
+		__field(unsigned int, flush_merge)
 	),
 
 	TP_fast_assign(