spl_perform_fixups is redundant in the current implementation. SPLs call
dram_init during spl_enable_cache in arch/arm/mach-k3/common.c. In
U-Boot, dram_init and dram_init_banksize are automatically called in
init_sequence_f. Therefore, SPLs and U-Boot always determine the correct
RAM size. During Linux boot, fdt_fixup_memory_banks adjusts the RAM size
in the Linux device tree, ensuring correct RAM usage.

dram_init() calls get_ram_size() for the Verdin AM62, which determines
the correct RAM size through read/write operations. However, due to the
K3 bootflow placing ATF in RAM and requiring cache coherence, calling
get_ram_size() with caches enabled prevents ATF boot. Removing this call
restores ATF boot functionality.

This fixes a regression introduced in commit 4164289d ("board:
verdin-am62: fix missing memory fixup call") which prevents some of our
Verdin AM62 modules from booting.

Fixes: 4164289d ("board: verdin-am62: fix missing memory fixup call")
Signed-off-by: Stefan Eichenberger <stefan.eichenberger@toradex.com>