freedreno: do not leak drmVersion

Cc: Rob Clark <robclark@freedesktop.org>
Signed-off-by: Emil Velikov <emil.l.velikov@gmail.com>
Reviewed-by: Rob Clark <robdclark@gmail.com>
Signed-off-by: Rob Clark <robclark@freedesktop.org>
freedreno: zero out unused field

Since realloc() doesn't zero-init.

Signed-off-by: Rob Clark <robclark@freedesktop.org>