Enable LRA on several ports

Enable LRA on several ports

Spurred by Segher's RFC, I went ahead and tested several ports with LRA
enabled.  Not surprisingly, many failed, but a few built their full set
of libraries successful and of those a few even ran their testsuites
with no regressions.  In fact, enabling LRA fixes a small number of
failures on the iq2000 port.

This patch converts the ports which built their libraries and have test
results that are as good as or better than without LRA.    There may
be minor code quality regressions or there may be minor code quality
improvements -- I'm leaving that for the port maintainers to own going
forward.

gcc/

	* config/cris/cris.cc (TARGET_LRA_P): Remove.
	* config/epiphany/epiphany.cc (TARGET_LRA_P): Remove.
	* config/iq2000/iq2000.cc (TARGET_LRA_P): Remove.
	* config/m32r/m32r.cc (TARGET_LRA_P): Remove.
	* config/microblaze/microblaze.cc (TARGET_LRA_P): Remove.
	* config/mmix/mmix.cc (TARGET_LRA_P): Remove.