We should include headers that C files use in the C files that use them
and avoid relying on implicit includes as much as possible. This helps
avoid compiler errors in the future about missing declarations when
header files change includes in the future.

Cc: Douglas Anderson <dianders@chromium.org>
Cc: Suzuki K Poulose <suzuki.poulose@arm.com>
Cc: Mike Leach <mike.leach@linaro.org>
Signed-off-by: Stephen Boyd <swboyd@chromium.org>
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Link: https://lore.kernel.org/r/20200518180242.7916-20-mathieu.poirier@linaro.orgSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>