New Sanyo Stormy16 relocations

[DJ Delorie]

I'm committing this approved patch on Andrew's behalf.  The cgen parts
were approved by FChE off-list.

> bfd/ChangeLog
> 	* elf32-xstormy16.c (xstormy16_elf_howto): Add R_XSTORMY16_LO16
> 	and R_XSTORMY16_HI16) howto entries.
> 	(xstormy16_reloc_map): Map R_XSTORMY16_{LO,HI}16 to BFD_RELOC_{LO,HI}16.
> 	(xstormy16_info_to_howto_rela): Use R_XSTORMY16_GNU_VTINHERIT to 
> 	determine the start of the second reloc table.
> 
> cgen/ChangeLog
> 	* cpu/xstormy16.cpu (imm16): Call handler immediate16.
> 	* cpu/xstormy16.opc (parse_small_immediate): Return on '@'.
> 	(parse_immediate16): Handle immediate16 values, which now include
> 	@hi(label) and @lo(label)
> 
> gas/ChangeLog
> 	* config/tc-xstormy16.c (md_cgen_lookup_reloc): If a relocation 
> 	has already been set up, use it.
> 
> include/ChangeLog
> 	* elf/xstormy16.h (START_RELOC_NUMBERS) Add relocation numbers
> 	for R_XSTORMY16_LO16 and R_XSTORMY16_HI16.
> 
> opcodes/ChangeLog
> 	* opcodes/xstormy16-asm.c: Regenerate.