SGX SDK's sgx_init_quote may return SGX_ERROR_BUSY, which is previously not
handled. The implementation of ioctl for /dev/sgx is now fixed to handle this
error.
1. Introduce the new infrastructure for ioctl support
2. Refactor the old ioctls to use the new infrastructure
3. Implement builtin ioctls (e.g., TIOCGWINSZ and TIOCSWINSZ for stdout)
4. Implement non-builtin, driver-specific ioctls (e.g., ioctls for /dev/sgx)