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

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

This reverts commit b4e1668109ba03660a46660a8f389997f7dc3835.

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