RISC-V: Add -malign-data= option.

RISC-V: Add -malign-data= option.

	gcc/
	Ilia Diachkov  <ilia.diachkov@optimitech.com>
	* config/riscv/riscv-opts.h (struct riscv_align_data): New.
	* config/riscv/riscv.c (riscv_constant_alignment): Use
	riscv_align_data_type.
	* config/riscv/riscv.h (RISCV_EXPAND_ALIGNMENT): New.
	(DATA_ALIGNMENT): Use RISCV_EXPAND_ALIGNMENT.
	(LOCAL_ALIGNMENT): Use RISCV_EXPAND_ALIGNMENT.
	* config/riscv/riscv.opt (malign-data): New.
	* doc/invoke.texi (RISC-V Options): Document -malign-data=.

From-SVN: r273714