frame_superres: Use calculate_scaled_size for scale check
frame_superres: Use calculate_scaled_size for scale check

Small change to calculate the encode size for scale checking using the
av1_calculate_scaled_size function used elsewhere instead of calculating
it in place. Done for constistency's sake.

Change-Id: I72626b729477e28e868cf9028ea4537267a12413

GrokImageCompression/aom,GrokImageCompression/aom,GrokImageCompression/aom,GrokImageCompression/aom,GrokImageCompression/aom,GrokImageCompression/aom