video: tegra: nvmap: Refactor nvmap_dev unit

- Add nvmap_dev.h file which include declaration for functions and data
structs which are exposed by nvmap_dev unit to other units.
- Also, add nvmap_dev_int.h file which include declaration for
functions which are internal to nvmap_dev unit that can be called by
files within nvmap_dev unit.
- Move definition of nvmap_handle_get_from_id, nvmap_install_fd,
find_range_of_handles to nvmap_handle.c as they belong to nvmap_handle
unit.
- Cleanup nvmap_priv.h by moving all relevant items for nvmap_dev unit
to nvmap_dev unit.
- Remove nvmap_mm.c file as nvmap_zap_handle is the only function
present; move it to nvmap_cache.c where it's being called.
- Remove function declarations whose definition are not present.

JIRA TMM-5694
JIRA TMM-5730

Change-Id: Ifd45235076da2ef0c628f3179d828c0ccadf6df2
Signed-off-by: Ketan Patil <ketanp@nvidia.com>
Reviewed-on: https://git-master.nvidia.com/r/c/linux-nv-oot/+/3223994
Reviewed-by: Pritesh Raithatha <praithatha@nvidia.com>
GVS: buildbot_gerritrpt <buildbot_gerritrpt@nvidia.com>

drivers/video/tegra/nvmap/nvmap_fault.c

@@ -9,6 +9,7 @@
 #include <linux/highmem.h>
 
 #include "nvmap_priv.h"
+#include "nvmap_dev.h"
 #include "nvmap_alloc.h"
 #include "nvmap_handle.h"