scripts: dtc: Remove the unused fdtdump.c file

This was copied from external DTC repository long back and isn't used
anymore. Over that the dtc tool can be used to generate the dts source
back from the dtb. Remove the unused fdtdump.c file.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/7ea1a9e7fd5d75b7adfc2a4c40dde2d4ea3fddf8.1611904394.git.viresh.kumar@linaro.org