MC ParamUpmix data type mismatch

As part of MC ParamUpmix structure, there is defined a flag:

typedef struct ivas_mc_paramupmix_enc_data_structure
{
    ...
    bool first_frame;
} MC_PARAMUPMIX_ENC_DATA, *MC_PARAMUPMIX_ENC_HANDLE;

while it holds values first_frame = 0 or first_frame = 1.

Strictly speaking, the data type of this parameter should be int16_t to avoid data type mismatch.

Alternatively, the flag could hold first_frame = false or first_frame = true but this is less preferable as the codec does not use bool except of the application layer.