ANDROID: Fix libfdt dependency

Currently, when building the DT lexer and parser for the host, it's
possible for a system DT header to be included instead of the local
version.

This issue was caught by accidentally building the host tools with
a cross-toolchain which did not supply the header.

To fix, add the correct dependency supplying the header to the
dtc_gen rule.

Change-Id: Icb6546b3f52c721697434394d6659301aa888ad2
Signed-off-by: John Moon <quic_johmoo@quicinc.com>

BUILD.dtc

@@ -47,6 +47,7 @@ cc_library(
         ":parser",
     ] + glob(["*.h"]),
     includes = ["."],
+    deps = [":libfdt"],
     visibility = ["//visibility:public"],
 )