arm: mach-k3: j721e: Improve support for UDA FS

Commit 50191709 ("arch: arm: mach-k3: j721e: add support for UDA
FS") introduced basic UDA FS support, however, we can Take approach
similar to commit 0f1c1e8b ("arm: mach-k3: am625: Add support for
UDA FS"). While boot partition support with EMMC boot is useful, it is
constrained by the size of boot hardware partition itself.

In the case of K3 devices, tispl images can contain OP-TEE images that
can substantially vary in size and the u-boot image itself can vary over
time as we enable various features.

So use the CSD information in the case of EMMC_BOOT configuration being
enabled to pick boot partition or UDA FS mode operation to pick.

If EMMC_BOOT is disabled, then depend on filesystem configuration to
pick data from UDA.

Signed-off-by: Nishanth Menon <nm@ti.com>