v4l: ioctl: Use %p4cc printk modifier to print FourCC codes

Now that we can print FourCC codes directly using printk, make use of the
feature in V4L2 core.

Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Acked-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Link: https://patchwork.freedesktop.org/patch/msgid/20210216155723.17109-3-sakari.ailus@linux.intel.com