Remove KERNEL_AIO dependency to avoid recursive dependency with libaio in
a future commit.

Signed-off-by: Rosen Penev <rosenp@gmail.com>

Signed-off-by: Maxim Storchak <m.storchak@gmail.com>

- Include `sys/user.h` if `__WORDSIZE` is undefined
 - Add `fcntl.h` to `libscc.c` in order to declare `loff_t`

Signed-off-by: Jo-Philipp Wich <jow@openwrt.org>