soc: qcom: pil: Add flag to know if modem SSR happened.

Introduce a flag to know if modem is restarting from cold boot or from
SSR.
Use this flag to decide if modem memory needs to be assigned back to
linux. After cold boot linux already owns modem memory and trying to
assign it back from modem is incorrect.

CRs-Fixed: 1050153
Change-Id: I1c1ef35ea7ef6c2552a22b85c5af260ade413777
Signed-off-by: Puja Gupta <pujag@codeaurora.org>