xilinx: Add env redund offset

xilinx: Add env redund offset

ENV_OFFSET_REDUND config is by default set to 0 for flashes. Saving the env
variables is overwriting data at 0 offset, which is wrong. So add default
redund env offset for Zynq, ZynqMP, Versal and microblaze platforms.
Configured ENV_OFFSET_REDUND offsets by ENV_OFFSET + (2 * ENV_SIZE).

In case of versal, we configured ENV_OFFSET_REDUND at 0x7F00000 instead
of 0x7F80000. As BOOT_SCRIPT_OFFSET is already configured at 0x7F80000.

Added ENV_OFFSET_REDUND in Kconfig for microblaze due to dependency of
ENV_IS_IN_SPI_FLASH config.

Below table specifies platform specific env and env redund offsets.

PLAT		ENV_OFFSET	ENV_OFFSET_REDUND
----		----------	-----------------
ZYNQ		0xE0000		0xE40000
ZYNQMP		0x1E00000	0x1E80000
VERSAL		0x7F40000	0x7F00000
MICROBLAZE	0x1080000	0x10C0000

Signed-off-by: T Karthik Reddy <t.karthik.reddy@xilinx.com>
Signed-off-by: Michal Simek <michal.simek@amd.com>
Link: https://lore.kernel.org/r/92656dc08f0f5a749d62b71ca6e77fe1be72e9e0.1661340204.git.michal.simek@amd.com