power: reset: fix bug on warm reset or hard reset selection

Rebooting to recovery, bootloader and rtc should be treated as
hard reset if PMIC sparse regs are used to store reset reason.
Otherwise it should be set as warm reset to keep compatible with
legacy design. So correct logic of need_warm_reset here.

Change-Id: Ica173cc379df16a28f11bf5da87cb928e73ecdfb
Signed-off-by: Lijuan Gao <lijuang@codeaurora.org>
Signed-off-by: Ashay Jaiswal <ashayj@codeaurora.org>