net: wireless: bcmdhd: Fix LP0 in case of wifi tethering

net: wireless: bcmdhd: Fix LP0 in case of wifi tethering

PROPTX_STATUS periodically sends useful information (such as
flow control info, RSSI etc) to the host, this prevents host from
going into LP0 mode. Disable dhd_pm_callback pm notifier
to fix this issue.

bug 200016824

Change-Id: I50c0fa61e6a183d203f8ef49b1ed81a060e81351
Signed-off-by: Manikanta <mmaddireddy@nvidia.com>
Reviewed-on: http://git-master/r/432654
Reviewed-by: Nagarjuna Kristam <nkristam@nvidia.com>
GVS: Gerrit_Virtual_Submit
Reviewed-by: Bharat Nihalani <bnihalani@nvidia.com>