Change use of eob in the encoder

Change use of eob in the encoder

Changed 'int eob' to 'char *eob' in BLOCKD so that both encoder and
decoder will use eobs[25] array from MACROBLOCKD structure. In future,
this will enable use of the decoder side IDCT in the encoder.

Change-Id: I6e1c011628cb8864fd4a0b80f0279ce16a5ca978