Fix the delta_time_ms types mismtach in btsnooz.py

The delta_time_ms field in btif_debug_btsnoop.h is 32 bits. The offset
count for 64 bits, and cause the decoder error. Change the offset back
for 32 bits.

Bug: 175283029
Test: ./btsnooz.py bugreport-WXYZ.txt
Change-Id: I28324c4ff33ab817dbad5c813616a8e8c994ff2a