arm64: dts: renesas: r8a7795: Add usb companion property in EHCI

This patch adds the "companion" property in the EHCI ch0, ch1 and
ch2 nodes to wait for the usb companion controller startup at resume.

Signed-off-by: Kazuya Mizuguchi <kazuya.mizuguchi.ks@renesas.com>
Signed-off-by: Takeshi Kihara <takeshi.kihara.df@renesas.com>
[remove ch3 node and revise the commit log]
Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>

Signed-off-by: Simon Horman <horms+renesas@verge.net.au>