etna: more robust cmdbuffer flush handling

When something goes wrong during reserve, abort with an error, as it means
that the command buffer is in inconsistent state.

Also work around an apparent Vivante kernel driver bug that results in
hangs.
native: Remove symlinks.

 - Symlinks point to some local files, probably not needed.
 - Symlinks are breaking ptp-sync commit and disable synchronization feature.
add mth in to authors in README
README update
kernel_drivers: Add driver imported from Freescale BSP release 4.0.0.

Original source:
 - repository: git://git.freescale.com/imx/linux-2.6-imx.git
 - branch: imx_3.0.35_4.0.0
 - tag: rel_imx_3.0.35_4.0.0
 - commit id: 54750ff96a725ed78c057bc386d0f210c34bc53c

Driver tested with gpu-viv binary driver released by timesys:
 - gpu-viv-bin-mx6q-3.0.35-4.0.0.tar.gz
 - download link: http://repository.timesys.com/buildsources/g/gpu-viv-bin-mx6q/gpu-viv-bin-mx6q-3.0.35-4.0.0/gpu-viv-bin-mx6q-3.0.35-4.0.0.tar.gz
kernel_headers: Add headers imported from Freescale BSP release 4.0.0

Original source:
 - repository: git://git.freescale.com/imx/linux-2.6-imx.git
 - branch: imx_3.0.35_4.0.0
 - tag: rel_imx_3.0.35_4.0.0
 - commit id: 54750ff96a725ed78c057bc386d0f210c34bc53c

Driver tested with gpu-viv binary driver released by timesys:
 - gpu-viv-bin-mx6q-3.0.35-4.0.0.tar.gz
 - download link: http://repository.timesys.com/buildsources/g/gpu-viv-bin-mx6q/gpu-viv-bin-mx6q-3.0.35-4.0.0/gpu-viv-bin-mx6q-3.0.35-4.0.0.tar.gz
replay: Adjust Makefile for native/replay.
 - Remove repeated -lm flag (supplied by native/Makefile.inc).
 - Clean build products for GC800 and GC2000 on make clean.
egl: Fix build of egl demos with DIRECTFB.
 - Vivante headers require -DLINUX and -DEGL_API_DFB to determine that
   target system uses DIRECTFB.
 - Directfb headers are not in standard path.
 - Linking egl demos breaks without -ldl flag.
Add egl that only cleans screen.

Useful when looking into new chip.
Move ioctl structure definitions to gc_abi.h