arm64: zynqmp: Enable DP driver for SOMs

DP DMA is already enabled that's why there is no reason to keep DP
disabled.

Signed-off-by: Michal Simek <michal.simek@amd.com>
Link: https://lore.kernel.org/r/15d16b4de933bfae108df6ca368eb2cdf916aa02.1683034376.git.michal.simek@amd.com