ARM: dts: dra7: update cpsw compatible

CPSW driver has been updated with compatibles for enabling errata
workarounds. So updating cpsw compatibles.

Signed-off-by: Mugunthan V N <mugunthanvnm@ti.com>
Acked-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: David S. Miller <davem@davemloft.net>