Raise MAC learning table capacity from 1,024 to 2,048 entries per bridge.

Raise MAC learning table capacity from 1,024 to 2,048 entries per bridge.

Given a possible 1,024 ports on a bridge the previous limit of 2,048
entries seems low.

If we want to increase this further we should introduce dynamic allocation
of table entries to avoid wasting memory in the common case.

CC: Keith Amidon <keith@nicira.com>