Fix typo in mb_config.pyl

I typo-ed the builder name, mispelled fuchsia

Bug: 758256
Change-Id: I75d94e0cd2b6ed13e67dbfe71ec9f85c229a75d0
Reviewed-on: https://chromium-review.googlesource.com/1142443Reviewed-by: John Budorick <jbudorick@chromium.org>
Commit-Queue: Stephen Martinis <martiniss@chromium.org>
Cr-Commit-Position: refs/heads/master@{#576230}

tools/mb/mb_config.pyl

@@ -585,7 +585,7 @@
       'closure_compilation': 'closure_compilation',
       'fuchsia_arm64': 'release_trybot_fuchsia_arm64',
       'fuchsia_arm64_cast_audio': 'release_trybot_fuchsia_arm64_cast_audio',
-      'fucshia-fyi-x64-dbg': 'debug_trybot_fuchsia',
+      'fuchsia-fyi-x64-dbg': 'debug_trybot_fuchsia',
       'fuchsia_x64': 'release_trybot_fuchsia',
       'fuchsia_x64_cast_audio': 'release_trybot_fuchsia_cast_audio',
       'layout_test_leak_detection': 'release_trybot',