Correct errors in comments. Delete all assembler comments.

Delete commented out patterns.  Delete all peepholes but two.
Delete all define_splits but one.  Delete all `combiner' patterns.
(mpy): Correct multiply latencies.
(needs_delay_slot, hit_stack, interrupt_function, in_delay_slot,
define_delay): Correct and/or simplify all reorg related definitions.
(addsi3_real): Delete.
(addsi3): Use arith_operand for argument 1.
(mulhisi3): Use arith_reg_operand not mac_operand.
(and_ffff, and_ff): Delete.
(andsi3): Handle constant 255 specially.
(rot*): Correct and/or simplify all rotate patterns.
(ashlsi3_k): Delete clobber of T bit.  Output add for 1 bit shift.
(ashlsi3_n, lshrsi3_n): Delete use of fake_shift.
(negc): Correct pattern by adding set of T bit.
(extend*): Delete 'u' and 'U' constraint cases.
(pop): Separate 'l' and 'x' constraint cases.
(movsi-1): Better code for move to T bit case.
(bsr, bsr_value, mac): Delete.

From-SVN: r8888