drm/msm: Add msm_gem_get_and_pin_iova()

drm/msm: Add msm_gem_get_and_pin_iova()

Add a new function to get and pin the iova memory in one
step (basically renaming the old msm_gem_get_iova function)
and switch msm_gem_get_iova() to only allocate an iova but
not map it in the IOMMU. This is only currently used by
msm_ioctl_gem_info() since all other users of of the iova
expect that the memory be immediately available.

Signed-off-by: Jordan Crouse <jcrouse@codeaurora.org>
Signed-off-by: Rob Clark <robdclark@gmail.com>