dma/idxd: configure maximum batch size to high value

When configuring an Intel DSA instance using the utility script
dpdk_idxd_cfg.py, explicitly set the max supported batch size value to a
high value, to ensure large bursts are supported if so desired. The
default in the linux kernel is now just 32 [1], which may not be
sufficient for all DPDK apps.

[1] https://lore.kernel.org/r/163528473483.3926048.7950067926287180976.stgit@djiang5-desk3.ch.intel.com

Cc: stable@dpdk.org
Signed-off-by: Bruce Richardson <bruce.richardson@intel.com>
Reviewed-by: Kevin Laatz <kevin.laatz@intel.com>