CHROMIUM: config: mediatek: Enable DRM_POWERVR_ROGUE

Enable the Imagination PowerVR Rogue GPU driver.

echo "CONFIG_DRM_POWERVR_ROGUE=y" \
  >> chromeos/config/arm64/chromiumos-mediatek.flavour.config
echo "CONFIG_DRM_POWERVR_ROGUE=y" \
  >> chromeos/config/arm64/chromiumos-arm64.flavour.config
chromeos/scripts/kernelconfig oldconfig

# select all defaults

Note: For chromeos-4.4, CONFIG_DRM_POWERVR_ROGUE_DVFS no longer exists.

Signed-off-by: Daniel Kurtz <djkurtz@chromium.org>
Signed-off-by: Rufus Hamade <rufus.hamade@imgtec.com>

BUG=chrome-os-partner:60805
TEST=build chromeos-4.4 for elm and boot
TEST=build chromeos-4.4 for kevin and boot

BUG=chrome-os-partner:40578
BUG=chrome-os-partner:45469
TEST=Boot oak-rev2 to UI, login and browse BBC website.
TEST=Verify devfreq sysfs node and devfreq entries [1]:
  ls -al /sys/class/devfreq/13000000.mfgsys-gpu/
  [1] https://www.kernel.org/doc/Documentation/ABI/testing/sysfs-class-devfreq
TEST=http://iacopoapps.appspot.com/hopalongwebgl/
  => MTKSysSetVolt and MTKSysSetFreq logs in dmesg
TEST=while ctrl-tab between hopalongwebgl and empty tab while doing:
  watch -n 0.1 cat /sys/class/devfreq/13000000.mfgsys-gpu/cur_freq
  => should alternate between high (494000) and low (253500) values

Reviewed-on: https://chromium-review.googlesource.com/269935

Change-Id: I014c64efb5eba927d322455de5b00b7e8e1dbf05
Reviewed-on: https://chromium-review.googlesource.com/423511
Commit-Ready: Daniel Kurtz <djkurtz@chromium.org>
Tested-by: Daniel Kurtz <djkurtz@chromium.org>
Reviewed-by: Nicolas Boichat <drinkcat@chromium.org>