bluetooth: hci_ath: enable driver support for bluedroid stack

Added module params to allow userspace to control the sleep
mechanism of atheros chipset.

Change-Id: Ie7a9a6c0d73d8df694c805f59a22ad9c52ea8c87
Signed-off-by: Pradeep Panigrahi <pradeepp@codeaurora.org>