zram: consolidate device-attr declarations

Do not spread device attributes declarations across
the file, move io_stat, mm_stat, debug_stat to a common
device-attr section.

Signed-off-by: Sergey Senozhatsky <senozhatsky@chromium.org>

Author: sergey-senozhatsky

drivers/block/zram/zram_drv.c

@@ -1966,10 +1966,6 @@ static ssize_t debug_stat_show(struct device *dev,
 	return ret;
 }
 
-static DEVICE_ATTR_RO(io_stat);
-static DEVICE_ATTR_RO(mm_stat);
-static DEVICE_ATTR_RO(debug_stat);
-
 static void zram_meta_free(struct zram *zram, u64 disksize)
 {
 	size_t num_pages = disksize >> PAGE_SHIFT;
@@ -3008,6 +3004,9 @@ static const struct block_device_operations zram_devops = {
 	.owner = THIS_MODULE
 };
 
+static DEVICE_ATTR_RO(io_stat);
+static DEVICE_ATTR_RO(mm_stat);
+static DEVICE_ATTR_RO(debug_stat);
 static DEVICE_ATTR_WO(compact);
 static DEVICE_ATTR_RW(disksize);
 static DEVICE_ATTR_RO(initstate);