ARM: dts: am5729: beagleboneai: switch to new cpsw switch drv

Switch BeagleBone AI to use new cpsw switch driver.
It has one Ext. port only and fits dual_mac mode with no issues.

Signed-off-by: Grygorii Strashko <grygorii.strashko@ti.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>