of: reserved_mem: Fix kmemleak crash on no-map region

Unable to handle kernel paging request at virtual address
[<ffffff849b434d88>] scan_block+0x88/0x170
[<ffffff849b435070>] scan_gray_list+0x18c/0x1c0
[<ffffff849b4352ac>] kmemleak_scan+0x208/0x4b0
[<ffffff849b4359ec>] kmemleak_write+0x338/0x378
[<ffffff849b571068>] full_proxy_write+0x80/0xe4
[<ffffff849b43fe7c>] vfs_write+0xb4/0x1d0

early_init_dt_alloc_reserved_memory_arch() calls memblock_alloc_base(),
which will create a kmemleak entry. Ensure this entry is ignored if
the no-map property is set. This will prevent kmemleak from scanning
the object if there is no kernel mapping for it.

Change-Id: I45f35600ae2aacf0f10f8bcbc956d019b666e4a7
Signed-off-by: Patrick Daly <pdaly@codeaurora.org>
Signed-off-by: Sudarshan Rajagopalan <sudaraja@codeaurora.org>