ada: Implement fast modulo reduction for nonbinary modular multiplication

ada: Implement fast modulo reduction for nonbinary modular multiplication

This adds the missing guard to prevent the reduction from being used when
the target does not provide or cannot synthesize a high-part multiply.

gcc/ada/

	* gcc-interface/trans.cc (gnat_to_gnu) <N_Op_Mod>: Fix formatting.
	* gcc-interface/utils2.cc: Include optabs-query.h.
	(fast_modulo_reduction): Call can_mult_highpart_p on the TYPE_MODE
	before generating a high-part multiply.  Fix formatting.