posix file: Add procedure to query the size of a file

Change-Id: Ib3b31e90ca98dc09185463ce467a70770e0f222d
Signed-off-by: Nico Huber <nico.h@gmx.de>
Reviewed-on: https://review.coreboot.org/21095
Reviewed-by: Arthur Heymans <arthur@aheymans.xyz>
2 files changed