media: synopsys: hdmirx: Fix signedness bug in hdmirx_parse_dt()

The num_clks is set this way:

	hdmirx_dev->num_clks = devm_clk_bulk_get_all(dev, &hdmirx_dev->clks);
        if (hdmirx_dev->num_clks < 1)
                return -ENODEV;

The devm_clk_bulk_get_all() function returns negative error codes so the
hdmirx_dev->num_cks variable needs to be signed for the error handling to
work.

Fixes: 7b59b132 ("media: platform: synopsys: Add support for HDMI input driver")
Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
Reviewed-by: Dmitry Osipenko <dmitry.osipenko@collabora.com>
Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>