ARM: dts: DRA7X: drop id property in pcie_phy

Since phyid is no longer used by pcie driver, this field can be dropped
from the DT.

Signed-off-by: Vignesh R <vigneshr@ti.com>
Acked-by: Kishon Vijay Abraham I <kishon@ti.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>