AVR32 support by Hans-Christian Egtvedt

AVR32 support by Hans-Christian Egtvedt
(hans-christian.egtvedt AT atmel.com).
* configure.ac: Make it recognize avr32.
* defs.h: Define LINUX_AVR32.
* linux/avr32/syscallent.h: New file.
* Makefile.am: Reference linux/avr32/syscallent.h.
* proc.c (change_syscall, setarg): Add support for avr32.
(struct xlat struct_user_offsets[]): Ditto.
* syscall.c (get_scno): Ditto.
(get_error, force_result, syscall_enter): Ditto.
* util.c (getpc, printcall): Ditto.