media: Revert cleanup ktime_set() usage

This reverts 8b0e1953, because media-tree drivers should use the
API functions to initialize variables of type ktime_t.

Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Jasmin Jessich <jasmin@anw.at>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>