drm/i915: Pull GEM ioctls interface to its own file

Declutter i915_drv/gem.h by moving the ioctl API into its own header.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Matthew Auld <matthew.auld@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190528092956.14910-2-chris@chris-wilson.co.uk
diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index 902162c..aed9f36 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -39,6 +39,7 @@
 #include <linux/dma-buf.h>
 #include <linux/mman.h>
 
+#include "gem/i915_gem_ioctls.h"
 #include "gt/intel_engine_pm.h"
 #include "gt/intel_gt_pm.h"
 #include "gt/intel_mocs.h"