s390/protvirt: use scnprintf() instead of snprintf()

snprintf() returns the number of bytes that would be written,
which may be greater than the the actual length to be written.

uv_query_facilities() should return the number of bytes printed
into the buffer. This is the return value of scnprintf().
The other functions are the same.

Link: https://lkml.kernel.org/r/20200509085608.41061-4-chenzhou10@huawei.comSigned-off-by: Chen Zhou <chenzhou10@huawei.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>

arch/s390/kernel/uv.c

@@ -331,7 +331,7 @@ EXPORT_SYMBOL_GPL(arch_make_page_accessible);
 static ssize_t uv_query_facilities(struct kobject *kobj,
 				   struct kobj_attribute *attr, char *page)
 {
-	return snprintf(page, PAGE_SIZE, "%lx\n%lx\n%lx\n%lx\n",
+	return scnprintf(page, PAGE_SIZE, "%lx\n%lx\n%lx\n%lx\n",
 			uv_info.inst_calls_list[0],
 			uv_info.inst_calls_list[1],
 			uv_info.inst_calls_list[2],
@@ -344,7 +344,7 @@ static struct kobj_attribute uv_query_facilities_attr =
 static ssize_t uv_query_max_guest_cpus(struct kobject *kobj,
 				       struct kobj_attribute *attr, char *page)
 {
-	return snprintf(page, PAGE_SIZE, "%d\n",
+	return scnprintf(page, PAGE_SIZE, "%d\n",
 			uv_info.max_guest_cpus);
 }
 
@@ -354,7 +354,7 @@ static struct kobj_attribute uv_query_max_guest_cpus_attr =
 static ssize_t uv_query_max_guest_vms(struct kobject *kobj,
 				      struct kobj_attribute *attr, char *page)
 {
-	return snprintf(page, PAGE_SIZE, "%d\n",
+	return scnprintf(page, PAGE_SIZE, "%d\n",
 			uv_info.max_num_sec_conf);
 }
 
@@ -364,7 +364,7 @@ static struct kobj_attribute uv_query_max_guest_vms_attr =
 static ssize_t uv_query_max_guest_addr(struct kobject *kobj,
 				       struct kobj_attribute *attr, char *page)
 {
-	return snprintf(page, PAGE_SIZE, "%lx\n",
+	return scnprintf(page, PAGE_SIZE, "%lx\n",
 			uv_info.max_sec_stor_addr);
 }