Minor bug in loading vocoders

[Mahyar24]

These three lines don't load the models into the desired device and should be replaced:

FastSpeech2/utils/model.py

Line 20 in d4e79eb

ckpt = torch.load(ckpt_path)

FastSpeech2/utils/model.py

Line 63 in d4e79eb

ckpt = torch.load("hifigan/generator_LJSpeech.pth.tar")

FastSpeech2/utils/model.py

Line 65 in d4e79eb

ckpt = torch.load("hifigan/generator_universal.pth.tar")

with something like this: torch.load(ckpt_path, map_location=device).