ARM64: dts: provide adc conversion delay value

ARM64: dts: provide adc conversion delay value

Providing adc conversion delay value to wait
before reading conversion data.

Change-Id: Iac48d245716d6c921f17e4e006af358b3c315306
Signed-off-by: Venkat Reddy Talla <vreddytalla@nvidia.com>
Reviewed-on: http://git-master/r/763610
(cherry picked from commit 5bd1cae55ff6923dd0d73a5dc9f5fbcd7dad0e73)
Signed-off-by: Venkat Reddy Talla <vreddytalla@nvidia.com>
Reviewed-on: http://git-master/r/764891
Reviewed-by: Laxman Dewangan <ldewangan@nvidia.com>
Tested-by: Laxman Dewangan <ldewangan@nvidia.com>