qlcnic: add eswitch statistics support

Adding eswitch statistics support. User can get
whole eswitch stats or stats of func belong to that eswitch.

Added:
o command to get statistics of eswitch and function.
o sysfs support to export eswitch and func statatistics.

Signed-off-by: Amit Kumar Salecha <amit.salecha@qlogic.com>
Signed-off-by: David S. Miller <davem@davemloft.net>