ath6kl: Do not generate random MAC always.

This patch removes the functionality of generating random MAC
address every time. With this patch Random MAC will be generated
only if module parameter is passed.

Change-Id: I2322960bac5d98972e36f9f58a95918a591d40a7

Signed-off-by: Ram Ranganathan <rrangana@qca.qualcomm.com>