The last 4 MiB of RAM on those devices is likely used by trustzone
firmware, and is unusable under Linux. Change the device tree memory
node accordingly.

The proprietary bootloader (S-BOOT) passes these memory ranges through
ATAG_MEM; this change allows us to have the correct memory ranges
without relying on ATAG_MEM.

Tested-by: Henrik Grimler <henrik@grimler.se> # i9300, i9305
Signed-off-by: Artur Weber <aweber.kernel@gmail.com>
Link: https://lore.kernel.org/r/20240217-exynos4-memsize-fix-v1-1-7858e9c5f844@gmail.comSigned-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>