drivers: net: cpsw: use module_platform_driver

There is no reasons to probe cpsw from late_initcall level
and it's not recommended. Hence, use module_platform_driver()
to register and probe cpsw driver from module_init() level.

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