arch/i386/kernel/apm.c: fix sparse warnings

Index: linux-2.6.11-bk1-sparse/arch/i386/kernel/apm.c
===================================================================
@@ -346,10 +346,10 @@ extern int (*console_blank_hook)(int);
 struct apm_user {
 	int		magic;
 	struct apm_user *	next;
-	int		suser: 1;
-	int		writer: 1;
-	int		reader: 1;
-	int		suspend_wait: 1;
+	unsigned int	suser: 1;
+	unsigned int	writer: 1;
+	unsigned int	reader: 1;
+	unsigned int	suspend_wait: 1;
 	int		suspend_result;
 	int		suspends_pending;
 	int		standbys_pending;