avr32: Use generic posix_types.h

Change the avr32 architecture to use <asm-generic/posix_types.h>.

Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Link: http://lkml.kernel.org/r/1328677745-20121-6-git-send-email-hpa@zytor.com
Cc: Haavard Skinnemoen <hskinnemoen@gmail.com>
Cc: Hans-Christian Egtvedt <egtvedt@samfundet.no>