dt-bindings: phy: ti,phy-j721e-wiz: fix bindings for torrent phy

When WIZ wraps a Cadence Torrent PHY (instead of Cadence Sierra PHY)
there is a difference in the refclk-dig node: Torrent only has two
clocks instead of Sierra's four clocks. Add minItems: 2 to solve this.

Additionally, in our use case we only need to use assigned-clock for a
single clock, but the current binding requires either no assigned-clocks
or two. Fix this by adding minItems: 1 to all the assigned-clock
properties.

There was also an extra trailing whitespace, which this patch removes.

Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>
Link: https://lore.kernel.org/r/20200918083743.213874-2-tomi.valkeinen@ti.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>