Revert "arm64: zynqmp: Add zynqmp firmware specific DT nodes"

Revert "arm64: zynqmp: Add zynqmp firmware specific DT nodes"

This reverts commit 50a6bd000f94832658f42fb01b9aaf9e39a52004.

As zynqmp mini emmc does not rely on firmware, remove firmware related
device tree modes from zynqmp mini emmc dts files.

Signed-off-by: T Karthik Reddy <t.karthik.reddy@xilinx.com>
Acked-by: Ashok Reddy Soma <ashok.reddy.soma@xilinx.com>
Signed-off-by: Michal Simek <michal.simek@amd.com>
Link: https://lore.kernel.org/r/e69b30d82b0307c563fe72630d9172e53964aeda.1652262769.git.michal.simek@amd.com