drm/i915: kill i915_mem.c

Some decent history digging indicates that this was to be used for the
GLX_MESA_allocate_memory extension but never actually implemented for
any released i915 userspace code.

So just rip it out.

v2: Fixup the Makefile.

Acked-by: Dave Airlie <airlied@gmail.com>
Cc: Keith Whitwell <keithw@vmware.com>
Reviewed-by: Eric Anholt <eric@anholt.net>
Signed-Off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/drm_ioctl.c

@@ -37,6 +37,7 @@
 #include "drm_core.h"
 
 #include "linux/pci.h"
+#include "linux/export.h"
 
 /**
  * Get the bus id.
@@ -346,3 +347,4 @@ int drm_noop(struct drm_device *dev, void *data,
 	DRM_DEBUG("\n");
 	return 0;
 }
+EXPORT_SYMBOL(drm_noop);