net: Stop conflating return value with file size in net_loop()

net: Stop conflating return value with file size in net_loop()

The net_loop() currently conflates return value with file size
at the end of successful transfer, in NETLOOP_SUCCESS state.

The return type of net_loop() is int, which makes this practice
workable for file sizes below 2 GiB, but anything above that will
lead to overflow and bogus negative return value from net_loop().

The return file size is only used by a few sites in the code base,
which can be easily fixed. Change the net_loop() return value to
always be only a return code, in case of error the returned value
is the error code, in case of successful transfer the value is 0
or 1 instead of 0 or net_boot_file_size . This surely always fits
into a signed integer.

By keeping the return code 0 or 1 in case of successful transfer,
no conditionals which depended on the old behavior are broken, but
all the sites had to be inspected and updated accordingly.

Fix the few sites which depend on the file size by making them
directly use the net_boot_file_size variable value. This variable
is accessible to all of those sites already, because they all
include net-common.h .

Signed-off-by: Yuya Hamamachi <yuya.hamamachi.sx@renesas.com>
Signed-off-by: Marek Vasut <marek.vasut+renesas@mailbox.org>