Add FT32B support

Add FT32B support

FT32B is a new FT32 architecture type. FT32B has a code compression
scheme which uses linker relaxations. It also has a security option to
prevent reads from program memory.

gcc/
	* config/ft32/ft32.c (ft32_addr_space_legitimate_address_p): increase
	offset range for FT32B.
	* config/ft32/ft32.h: option "mcompress" enables relaxation.
	* config/ft32/ft32.md: Add TARGET_NOPM.
	* config/ft32/ft32.opt: Add mft32b, mcompress, mnopm.
	* gcc/doc/invoke.texi: Add mft32b, mcompress, mnopm.

From-SVN: r254351