phy: cadence-torrent: Check total lane count for all subnodes is within limit

Add checking if total number of lanes for all subnodes is not greater than
number of lanes supported by PHY.

Signed-off-by: Swapnil Jakhade <sjakhade@cadence.com>
Link: https://lore.kernel.org/r/1600280911-9214-6-git-send-email-sjakhade@cadence.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>