[Fuchsia] Fix fidl_deps handling in fidl_library() GN template fidl_deps parameter in fidl_library() was broken by https://crrev.com/555215 . Bug: 831384 Change-Id: Iecda3f545f6818561422b556315175d1f4df1ec4 Reviewed-on: https://chromium-review.googlesource.com/1045405 Commit-Queue: Sergey Ulanov <[email protected]> Reviewed-by: Kevin Marshall <[email protected]> Cr-Original-Commit-Position: refs/heads/master@{#556939} Cr-Mirrored-From: https://chromium.googlesource.com/chromium/src Cr-Mirrored-Commit: 37c01931beb7bf08728a97d885ad37807dfe6309