Hello,
you can use the interface command:
storm-control unicast level 10.00
or
storm-control unicast bps 10000000
The first command will limit bandwidth to 10% of what is available, the second will limit bandwidth to 10Mbps, effectively achieving the same thing.
Check this link to the relevant configuration reference:
Configuring Storm Control
http://www.cisco.com/en/US/products/hw/switches/ps5023/products_configuration_guide_chapter09186a00802c10bc.html#wp1063295
HTH,
GP