Eliminate several useless ioctls and associated cruft.

The ioctlss XGI_ESC_DEVICE_INFO, XGI_ESC_MEM_COLLECT,
XGI_ESC_PCIE_CHECK, XGI_ESC_GET_SCREEN_INFO, XGI_ESC_PUT_SCREEN_INFO,
XGI_ESC_MMIO_INFO, and XGI_ESC_SAREA_INFO, are completely unnecessary.
The will be doubly useless when the driver is converted to the DRM
infrastructure.