board: ti: am574x-idk: Add ddr data support

AM574x-idk has the following DDR parts attached:
EMIF1: MT41K256M16HA (1GB with ECC)
EMIF2: MT41K256M16HA (1GB without ECC)

Enabling 2GB DDR without interleaving between EMIFs. And
enabling ECC on EMIF1.

Signed-off-by: Lokesh Vutla <lokeshvutla@ti.com>
Signed-off-by: Krunal Bhargav <k-bhargav@ti.com>