linux-user: Implement sync_file_range{,2} syscalls
Implement the missing syscalls sync_file_range and sync_file_range2.
The latter in particular is used by newer versions of apt on Ubuntu
for ARM.
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Riku Voipio <riku.voipio@iki.fi>