[brigfe] Small fixes

2017-01-27  Pekka Jaaskelainen  <pekka.jaaskelainen@parmance.com>

	* configure.ac: Moved the white list of enabling BRIG FE to
	libhsail-rt/configure.tgt.  
	* configure: Regenerated.
	* MAINTAINERS: Updated maintainers for BRIG FE and libhsail-rt.

gcc/
	* builtin-types.def: Use unsigned_char_type_node for BT_UINT8.  Use
	uint16_type_node for BT_UINT16.

gcc/brig/
	* config-lang.in: Removed stale target-libbrig reference.

libhsail-rt/
	* configure.tgt: Moved the white list of supported targets here
	from configure.ac.  Added i[3456789]86-*-linux* as a supported env
	for the BRIG FE.
	* README: Added a proper description of what libhsail-rt is.

From-SVN: r244978