avr32: add defines and prototype function for sync_file_range syscall
avr32: add defines and prototype function for sync_file_range syscall

This patch adds the needed defines and function prototype for the
sync_file_range syscall on AVR32 architecture.

Signed-off-by: Hans-Christian Egtvedt <3205290bd1d4a909d3b1f9e99f4a85bafd04fac3@atmel.com>

joel-porquet/tsar-uclibc,joel-porquet/tsar-uclibc,joel-porquet/tsar-uclibc,joel-porquet/tsar-uclibc