config/or1k/elf.h: Correct comment.

	* config/or1k/elf.h: Correct comment.
Add or1k*-*-rtems* target

	* config/or1k/rtems.h: New file.
	* gcc/config/or1k/t-rtems: New file.
	* gcc/config.gcc (or1k*-*-rtems*): Add RTEMS support.