ARM: DRA72x: fix io delay calibration for ethernet

we currently use in-development IODelay values for DRA72x which are
proposed in the data sheet, however, DRA72x EVM uses DP83865 ethernet
Phy over RGMII. The PHY characteristics and routing choices made on
the EVM, make the current iodelay values fail ethernet communication.

Instead, we need to choose custom values for DRA72x-evm specifically
designed for the PHY and routing on the platform for ethernet to
function.

Cc: Nishanth Menon <nm@ti.com>
Cc: Lokesh Vutla <lokeshvutla@ti.com>
Tested-by: Lokesh Vutla <lokeshvutla@ti.com>
Reviewed-by: Nishanth Menon <nm@ti.com>
Signed-off-by: Mugunthan V N <mugunthanvnm@ti.com>