staging: r8188eu: convert two functions from s32 to int

Convert the return type of fw_free_to_go() and
rtl8188e_firmware_download() from s32 to the more common int.

Signed-off-by: Michael Straube <straube.linux@gmail.com>
Link: https://lore.kernel.org/r/20220107103620.15648-13-straube.linux@gmail.com


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>