media: v4l: move helper functions for fractions from uvc to v4l2-common

The functions uvc_simplify_fraction and uvc_fraction_to_interval are
generic helpers which are also useful for other v4l2 drivers. This patch
moves them to v4l2-common.

Tested-by: Daniel Scally <dan.scally@ideasonboard.com>
Reviewed-by: Daniel Scally <dan.scally@ideasonboard.com>
Signed-off-by: Michael Grzeschik <m.grzeschik@pengutronix.de>
Link: https://lore.kernel.org/r/20220909221335.15033-2-m.grzeschik@pengutronix.de


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>