linux-user/syscall.c: Implement f and l versions of set/get/removexattr Implement the f and l versions (operate on fd, don't follow links) of the setxattr, getxattr and removexattr syscalls. Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Signed-off-by: Riku Voipio <riku.voipio@linaro.org>