i965: Clean up intel_batchbuffer_init().

i965: Clean up intel_batchbuffer_init().

Passing screen lets us get the kernel features, devinfo, and bufmgr,
without needing container_of.

This use of container_of could cause crashes due to issues with the
"sample" macro parameter.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=102062
Reviewed-by: Tapani Pälli <tapani.palli@intel.com>
Reviewed-by: Emil Velikov <emil.velikov@collabora.com>
Reviewed-by: Iago Toral Quiroga <itoral@igalia.com>