libdrm: add msm drm uapi header

msm_drm.h file Generated using make headers_install.

Generated from
tree - git://people.freedesktop.org/~airlied/linux


branch - drm-next
commit - 6d08b06e67cd117f6992c46611dfb4ce267cd71e

Remove freedreno/msm/msm_drm.h to maintain only
one copy of msm_drm.h and change freedreno Makefile
and meson.build file accordingly.

v2: Remove private freedreno/msm/msm_drm.h
v3: meson.build update
v3: README update (by anholt)

Signed-off-by: Tanmay Shah <tanmay@codeaurora.org>
Reviewed-by: Eric Anholt <eric@anholt.net>