Fixed usage of bc7enc.
Fixed usage of bc7enc.

Properly initialize the parameters. Since updating many new parameters were
added, so now call bc7enc_compress_block_params_init() to ensure they're
initialized.

Only call initialize for bc7e and bc7enc once during program execution.

akb825/Cuttlefish,akb825/Cuttlefish,akb825/Cuttlefish