Upgrade kernel and mesa for rpi2

AS-IS:

• Kernel: 4.1 and baserock/pedroalvarez/rpi2-drm-rebased-on-vc4-kms-v3d-rpi2 branch
• mesa: 11.0 (not official tag)

TO-BE:

• kernel: official release version more than 4.1 with vc4 drm
• mesa: 11.x with vc4 drm

Working items

1. Point out "dedd75f08ffe3360722ab761da18987aa681edd1" in meta-raspberrypi
2. Use official kernel (branch: rpi-4.1.y)
3. Upgrade mesa (Version: TBD)

Kernel change

DRM/VC4 is merged in RPI official kernel (git://github.com/raspberrypi/linux.git).

Working list referred by https://dri.freedesktop.org/wiki/VC4/

1. The Raspberry Pi Foundation's kernel tree now includes the driver in the current rpi-update 4.1 branch, and also the 4.5 branch.
    The devicetree has not been updated for the driver, so you can find a patch for that at: https://github.com/anholt/linux/tree/vc4-kms-v3d-squash-2-boot.
2. If you're starting from your own .config, you need CONFIG_DRM_VC4=y (not m, or it won't load) and CONFIG_I2C_BCM2835=y. CONFIG_FB_BCM2708 must be unset.