soc: qcom: socinfo: Protect current_image using semaphore lock.

Variable current_image can be modified by multiple threads.
This change will protect current_image getting modified
by multiple threads.

Change-Id: I33df463311b24f73b1ba124d388731a72bd13263
CRs-Fixed: 2016485
Signed-off-by: Swetha Chikkaboraiah <schikk@codeaurora.org>
Signed-off-by: Srinivasarao P <spathi@codeaurora.org>