genmodes.c: Change the word "bitsize" to "precision" throughout.

genmodes.c: Change the word "bitsize" to "precision" throughout.

	* genmodes.c: Change the word "bitsize" to "precision" throughout.
	* machmode.def: Likewise.
	* machmode.h (GET_MODE_SIZE): Cast value to unsigned short.
	(GET_MODE_BITSIZE): Define as GET_MODE_SIZE * BITS_PER_UNIT.
	(GET_MODE_PRECISION): New macro.
	(mode_bitsize): Renamed mode_precision.
	* stor-layout.c (mode_for_size, smallest_mode_for_size):
	Use GET_MODE_PRECISION; clarify comments.
ada:
	* misc.c (fp_prec_to_size, fp_size_to_prec): Use GET_MODE_PRECISION
	and update for changed meaning of GET_MODE_BITSIZE.

From-SVN: r73295