state: backend_raw: factor out state_backend_raw_file_get_size() into separate function
This patch factors out the state_backend_raw_file_get_size() into a separate
function and adds some ifdefs to make this code work under Linux aswell.
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>