msm: camera: Assign Null to unmapped addresses

Observed unhandled virtual addresses with all the camera drivers
while performing reads and writes to the ioremap addresses in different
scenarios, Hence assigining NULL to all the hardware remapped addresses
immediately after the iounmap calls

Signed-off-by: Lakshmi Narayana Kalavala <lkalaval@codeaurora.org>
(cherry picked from commit 72ee044121488cc9f4cde91c5e3a2b820d7a0fad)

[mikeioannina]: Cherry-pick for SEMC msm_vpe_standalone

Change-Id: Ia0a74ca35e8575b18da8350cb6de83752ee0b11b
Signed-off-by: Shruthi Krishna <skrish@codeaurora.org>
Signed-off-by: nobodyAtall <tsogkas@ceid.upatras.gr>