ARM: OMAP2+: am33xx: Add low level debugging support

Add support for low level debugging on AM335X EVM (AM33XX family).
Currently only support for UART1 console, which is used on AM335X EVM
is added.

Signed-off-by: Afzal Mohammed <afzal@ti.com>
Signed-off-by: Vaibhav Hiremath <hvaibhav@ti.com>
Reviewed-by: Kevin Hilman <khilman@ti.com>
Cc: Paul Walmsley <paul@pwsan.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>