msm: camera: icp: Change spin lock type

Change the spin lock to irq_save while setting the A5
irq callback so as to avoid stalling of the ISR.

Change-Id: I6df281f70d5207295340b33b6e0f02c2fbb30bb2
Signed-off-by: Karthik Anantha Ram <kartanan@codeaurora.org>