Update processor.v

/*
*[140604] modified to fit new "async_reg.v" and "prog_count.v"
*[140604] fix branch bug
*[140604] make some pipeline flushable and stallable
*[140604] move feedback pc_jumpaddrFB, pc_srcFB earlier to 3rd stage.
*         So branch taken will have penalty of 2 cycles
*/