ARM: dts: dra76-evm: Shift to using common IOdelay data

Now that we have a device-tree include file with common
MMC/SD IOdelay data for DRA76x SoC, shift the EVM device-tree
file to using that.

Tested-by: Jean-Jacques Hiblot <jjhiblot@ti.com>
Signed-off-by: Sekhar Nori <nsekhar@ti.com>
Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>