Roll Fuchsia SDK to 5c6db30993546cb0d76189c834697054ed5b680a

Includes changes to:
- Include the bootstrap service and default configuration in the bootfs.
- Support mmap()ing of files on tmpfs filesystems.

Bug: 707030
Change-Id: I4d3df8a0c2acc7bfaaa957f298dfddc8f567cbcb
Reviewed-on: https://chromium-review.googlesource.com/582048
Commit-Queue: Sergey Ulanov <sergeyu@chromium.org>
Reviewed-by: Sergey Ulanov <sergeyu@chromium.org>
Cr-Commit-Position: refs/heads/master@{#488835}

DEPS

@@ -1205,7 +1205,7 @@ hooks_os = {
       'action': [
         'python',
         'src/build/fuchsia/update_sdk.py',
-        '06ab789730c8f0749bda7eb4fd1e7988eccc38e0',
+        '5c6db30993546cb0d76189c834697054ed5b680a',
       ],
     },
   ],