thermal: nct72: report correct initial temperature & fix shutdown during bootup

thermal: nct72: report correct initial temperature & fix shutdown during bootup

If NCT is in standby mode, need to initiate one-shot conversion
before reading temperature, otherwise while bootup NCT will report
wrong initial temperature and driver will set wrong temperature
alert limits based on that.

While nct driver probe, enable oneshot conversion after
setting shutdown limits for local and external sensors.

Bug 1723265
Bug 200161159

Change-Id: I9080579be749fb26f51d4d1c28911db4b6538a70
Signed-off-by: Rajkumar Kasirajan <rkasirajan@nvidia.com>
Reviewed-on: http://git-master/r/1018100
Reviewed-on: http://git-master/r/929897
(cherry picked from commit 4164770df219bcd37ffa68950882564181a78e8f)
(cherry picked from commit baaa7aad03a9a49fb86f5f58c783920b906b0ee2)
Reviewed-on: http://git-master/r/1019841
(cherry picked from commit 67f749548ff94f6b76c203fe42c280d69b959008)
Reviewed-on: http://git-master/r/1022471
GVS: Gerrit_Virtual_Submit
Reviewed-by: Bibek Basu <bbasu@nvidia.com>
Reviewed-by: Laxman Dewangan <ldewangan@nvidia.com>