board: ti: am62x_evm: Add android bootflow

board: ti: am62x_evm: Add android bootflow

Add Android bootflow support for AM62X SK EVM board with
new android boot method.

To build for AM62x for Android, we use the
am62x_a53_android.config fragment when building A53 bootloaders:

  $ make am62x_evm_a53_defconfig
  $ make am62x_a53_android.config
  $ make

Co-developed-by: Mattijs Korpershoek <mkorpershoek@baylibre.com>
Signed-off-by: Mattijs Korpershoek <mkorpershoek@baylibre.com>
Signed-off-by: Guillaume La Roque <glaroque@baylibre.com>
Reviewed-by: Mattijs Korpershoek <mkorpershoek@baylibre.com>
Reviewed-by: Bryan Brattlof <bb@ti.com>