agp: add chipset flushing support to AGP interface

This bumps the AGP interface to 0.103.

Certain Intel chipsets contains a global write buffer, and this can require
flushing from the drm or X.org to make sure all data has hit RAM before
initiating a GPU transfer, due to a lack of coherency with the integrated
graphics device and this buffer.

This just adds generic support to the AGP interfaces, a follow-on patch
will add support to the Intel driver to use this interface.

Signed-off-by: Dave Airlie <airlied@redhat.com>

drivers/char/agp/backend.c

@@ -43,7 +43,7 @@
  * fix some real stupidity. It's only by chance we can bump
  * past 0.99 at all due to some boolean logic error. */
 #define AGPGART_VERSION_MAJOR 0
-#define AGPGART_VERSION_MINOR 102
+#define AGPGART_VERSION_MINOR 103
 static const struct agp_version agp_current_version =
 {
 	.major = AGPGART_VERSION_MAJOR,