fs_mgr: Fix ZRAM error when ZRAM disk size beyond (2^31-1) bytes

Because the zram_size type is unsigned int.so if ZRAM size great
than 2^31 -1, zram_fp will receive a negtive integer, while the
ZRAM driver only accept natural number.We need to use printf
formatting %u instand of %d.

Test: 1. Config the zramdisk size 2348810240 and build a ramdisk
      2. Reflash device and check below command:
         $adb shell dumpsys meminfo
         $ adb shell cat /sys/block/zram0/disksize
         ZRAM info display will be abnormal
      3. Config the zramdisk size 2348810240 and apply with this
         patch.
      4. Retest to step 2 and the ZRAM info will be ok.

Change-Id: I473de33fbd0b66cf13eac3172684e9fef11b6ef0
diff --git a/fs_mgr/fs_mgr.cpp b/fs_mgr/fs_mgr.cpp
index 73bdc7a..84981bf 100644
--- a/fs_mgr/fs_mgr.cpp
+++ b/fs_mgr/fs_mgr.cpp
@@ -1195,7 +1195,7 @@
                 ret = -1;
                 continue;
             }
-            fprintf(zram_fp, "%d\n", fstab->recs[i].zram_size);
+            fprintf(zram_fp, "%u\n", fstab->recs[i].zram_size);
             fclose(zram_fp);
         }