libdrm/exynos: fix usage of removed ioctls

[Tobias Jakobi]

Hello,

these two patches are needed for the exynos component of libdrm to
properly work again. With the current stable 3.18.x the 'exynos_bo_map'
call is broken, making it impossible to get data from userspace into
a DRM buffer.

The patches were sent by Hyungwon Hwang some while ago, but the first
one was very much broken, so I fixed it up. I've put the changelog
into the commit message itself.

Please apply so that the exynos component is useable again.

With best wishes,
Tobias