linux/sizes.h: sync from kernel

The kernel added SZ_4G macro in commit f2b9ba871b (arm64/kernel: kaslr:
reduce module randomization range to 4 GB).

Include linux/const.h for the _AC macro.

Drop a local SZ_4G definition in tegra code.

Cc: Tom Warren <twarren@nvidia.com>
Reviewed-by: Tom Rini <trini@konsulko.com>
Signed-off-by: Baruch Siach <baruch@tkos.co.il>
Signed-off-by: Stefan Roese <sr@denx.de>