entropy: correct elemental_duration_in_tc_minus1 with sub layers.

[cubicibo]

The description of elemental_duration_in_tc_minus1 says:

When HighestTid is equal to i and fixed_pic_rate_general_flag[ i ] is equal to 1 for a CVS containing picture n, the value computed for DpbOutputElementalInterval[ n ] shall be equal to ClockTick * ( elemental_duration_in_tc_minus1[ i ] + 1 ) [...]

With E-76, for progressive frames:

DpbOutputElementalInterval[ n ] = DpbOutputInterval[ n ] ÷ DeltaToDivisor = DpbOutputInterval[ n ] / 1

Thereby:

DpbOutputElementalInterval[ n ] = DpbOutputInterval[ n ] = ClockTick * (elemental_duration_in_tc_minus1[ i ] + 1)

With two layers, DpbOutputInterval[ n ] = 2 * ClockTick for every access unit belonging to the base layer: elemental_duration_in_tc_minus1 must be equal to (1 << (maxSubTLayers - i)) - 1 there.
The elemental duration, with three layers (60 fps at highestTid)
Base layer: 3 (15)
Layer 1: 1 (30)
Layer 2: 0 (60)