Add support for the AVR Tiny series of microcontrollers.

Add support for the AVR Tiny series of microcontrollers.

        * archures.c: add avrtiny architecture for avr target.
	* bfd-in2.h: Regenerate.
	* cpu-avr.c (arch_info_struct): add avrtiny arch info.
	* elf32-avr.c (elf_avr_howto_table): new relocation R_AVR_LDS_STS_16
	added for 16 bit LDS/STS instruction of avrtiny arch.
	(avr_reloc_map): reloc R_AVR_LDS_STS_16 is mapped to
	BFD_RELOC_AVR_LDS_STS_16.
	(bfd_elf_avr_final_write_processing): select machine number avrtiny arch.
	(elf32_avr_object_p): set machine number for avrtiny arch.
	* libbfd.h: Regenerate.
	* reloc.c: Add documentation for BFD_RELOC_AVR_LDS_STS_16 reloc.

         * config/tc-avr.c (mcu_types): Add avrtiny arch.
	Add avrtiny arch devices attiny4, attiny5, attiny9, attiny10, attiny20
	and attiny40.
	(md_show_usage): Add avrtiny arch in usage message.
	(avr_operand): validate and issue error for invalid register for avrtiny.
	add new reloc exp for 16 bit lds/sts instruction.
	(md_apply_fix): check 16 bit lds/sts operand for out of range and encode.
	(md_assemble): check ISA for arch and issue diagnostic.

	* include/elf/avr.h (E_AVR_MACH_AVRTINY): define avrtiny machine number.
	(R_AVR_LDS_STS_16): define 16 bit lds/sts reloc number.
	* include/opcode/avr.h (AVR_ISA_TINY): define avrtiny specific ISA.
	(AVR_ISA_2xxxa): define ISA without LPM.
	(AVR_ISA_AVRTINY): define avrtiny arch ISA.
	Add doc for contraint used in 16 bit lds/sts.
	Adjust ISA group for icall, ijmp, pop and push.
	Add 16 bit lds/sts encoding and update 32 bit lds/sts constraints.
	* opcodes/avr-dis.c (avr_operand): Handle constraint j for 16 bit lds/sts.
	(print_insn_avr): do not select opcode if insn ISA is avrtiny and machine
	is not avrtiny.

	* Makefile.am (ALL_EMULATION_SOURCES): add avrtiny emulation source.
	(eavrtiny.c): add rules for avrtiny emulation source.
	* Makefile.in: Regenerate.
	* configure.tgt: Add avrtiny to avr target emulations.
	* scripttempl/avrtiny.sc: New file.
	linker script template for avrtiny arch.
	* emulparams/avrtiny.sh: New file.
	emulation parameters for avrtiny arch.