MIPS patch: extendsidi2

[Jeffrey A Law]

  In message < m0y2eyf-0006vBC@cetus.cygnus.com >you write:
  > 
  > 
  > 
  > OK to push?
  > 
  > 
  > 	* mips.md (extendsidi2): Allow extension to/from a non-mips16 
  > 	register.
Looks reasonable to me.  Please install it.

jeff