broadcom/vc4: Bump libdrm requirement

Require a version of libdrm with syncobj support.

v2: Don't require a libdrm_vc4, just bump core libdrm if vc4 enabled (by
    anholt)

Signed-off-by: Stefan Schake <stschake@gmail.com>
Reviewed-by: Eric Anholt <eric@anholt.net>
2 files changed