More pdp11 warnings fixes

[Jeffrey A Law]

  In message < Pine.SOL.3.95q.990406180334.16636A-100000@red.csi.cam.ac.uk >you w
rite:
  > This patch fixes more warnings with the pdp11 target of egcs.
  > 
  > 1999-04-05  Joseph S. Myers  <jsm28@cam.ac.uk>
  > 
  > 	* pdp11.c (simple_memory_operand): Add default case in switch.
  > 	* pdp11.h (TARGET_SWITCHES): Add help strings.
  > 	(NOTICE_UPDATE_CC): Don't include excess argument to format.
  > 	(ASM_OUTPUT_DOUBLE_INT): Remove.
Thanks.  Installed.
jeff