video: tegra: nvmap: support zap VA->PA mappings

video: tegra: nvmap: support zap VA->PA mappings

Zapping VA->PA mapping is a necessary step to perform in order to
track if any page is accessed by CPU. Unless zapping is performed
a user space access would not result in a page fault and there is no
way nvmap can track it otherwise.

bug 1444151

Change-Id: Iee90b2c9db339d596f3d061aeaa1d2c210367778
Signed-off-by: Sri Krishna chowdary <schowdary@nvidia.com>
Reviewed-on: http://git-master/r/377861
(cherry picked from commit b2794a8b7c056acdfa22a67aed5fec7e4272aa45)
Reviewed-on: http://git-master/r/405096
GVS: Gerrit_Virtual_Submit
Reviewed-by: Bharat Nihalani <bnihalani@nvidia.com>