s390/appldata: make copy_from_user() invocations provably correct

Just change the type of "len" to unsigned int so the compiler can prove
that we don't have a buffer overflow (and generates less code).
We get rid of these:

In function 'copy_from_user',
    inlined from 'appldata_interval_handler' at
    arch/s390/appldata/appldata_base.c:265:
      uaccess.h:303: warning: call to 'copy_from_user_overflow' declared
      with attribute warning: copy_from_user() buffer size is not provably
      correct
In function 'copy_from_user',
    inlined from 'appldata_timer_handler' at
    arch/s390/appldata/appldata_base.c:225:
      uaccess.h:303: warning: call to 'copy_from_user_overflow' declared
      with attribute warning: copy_from_user() buffer size is not provably
      correct
In function 'copy_from_user',
    inlined from 'appldata_generic_handler' at
    arch/s390/appldata/appldata_base.c:333:
      uaccess.h:303: warning: call to 'copy_from_user_overflow' declared
      with attribute warning: copy_from_user() buffer size is not provably
      correct
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

arch/s390/appldata/appldata_base.c

@@ -204,7 +204,7 @@ static int
 appldata_timer_handler(ctl_table *ctl, int write,
 			   void __user *buffer, size_t *lenp, loff_t *ppos)
 {
-	int len;
+	unsigned int len;
 	char buf[2];
 
 	if (!*lenp || *ppos) {
@@ -246,7 +246,8 @@ static int
 appldata_interval_handler(ctl_table *ctl, int write,
 			   void __user *buffer, size_t *lenp, loff_t *ppos)
 {
-	int len, interval;
+	unsigned int len;
+	int interval;
 	char buf[16];
 
 	if (!*lenp || *ppos) {
@@ -290,7 +291,8 @@ appldata_generic_handler(ctl_table *ctl, int write,
 			   void __user *buffer, size_t *lenp, loff_t *ppos)
 {
 	struct appldata_ops *ops = NULL, *tmp_ops;
-	int rc, len, found;
+	unsigned int len;
+	int rc, found;
 	char buf[2];
 	struct list_head *lh;