Free space is miscalculated when starting db8

:Release Notes:
Fix calculating Free space

:Detailed Notes:
When starting db8, free space is calculated.
If free space is less than threshold, call factory reset.

Now, db8's partition size is 109,534,208(104.5M).
so threshold should be 4,929,039(104.5M * 45 / 1000 = 4.7M).

But actually, threshold is 634,072(0.6M).
Because $BYTES_TOTAL(109,534,208)*45 is over 32bit (0x125CB2C00).
0x125CB2C00 is became 0x25CB2C00 (634,072,000)

:Testing Performed:
Tested on TV with custom build

:QA Notes:

:Issues Addressed:
[ANG-6239] Free space is miscalculated when starting db8

Open-webOS-DCO-1.0-Signed-off-by: Youngseung Youngseung Ji <youngseung2.ji@lge.com>

Change-Id: I7f1a9692c00c62fb67d59eb749a5a51978fe9301
Reviewed-on: https://g2g.palm.com/5682
Reviewed-by: DCO Verification
Reviewed-by: Maksym Sditanov <maxim.sditanov@lge.com>
Tested-by: Maksym Sditanov <maxim.sditanov@lge.com>