fstab: correct zram parameter names

There was a report about warning during boot.

[libfs_mgr]Warning: unknown flag: zram_loopback_path=/data/per_boot/zram_swap
[libfs_mgr]Warning: unknown flag: zram_loopback_size=512M

We don't use zram_loopback_path any longer so remove it.
We also changed zram_loopback_size with zram_backingdev_size so correct it.

Bug: 145116439
Test: confirmed there is no warning and zram backing device was configured
Change-Id: If2146bd8e1755f3f71512d7204b07e1c7074bec7
Signed-off-by: Minchan Kim <minchan@google.com>
diff --git a/fstab.hardware b/fstab.hardware
index c224001..a3c9aa9 100644
--- a/fstab.hardware
+++ b/fstab.hardware
@@ -10,4 +10,4 @@
 /dev/block/bootdevice/by-name/misc                  /misc              emmc        defaults                                              defaults
 /dev/block/bootdevice/by-name/modem                 /vendor/firmware_mnt          vfat        ro,shortname=lower,uid=1000,gid=1000,dmask=227,fmask=337,context=u:object_r:firmware_file:s0   wait,slotselect
 /devices/platform/soc/a600000.ssusb/a600000.dwc3*   auto               vfat        defaults                                              voldmanaged=usb:auto
-/dev/block/zram0                                    none               swap        defaults                                              zramsize=2147483648,max_comp_streams=8,zram_loopback_path=/data/per_boot/zram_swap,zram_loopback_size=512M
+/dev/block/zram0                                    none               swap        defaults                                              zramsize=2147483648,max_comp_streams=8,zram_backingdev_size=512M