Both POSIX.1-2008 and Linux Programmer's Manual have a dedicated return
error code for a case, when a file doesn't support mmap(), it's ENODEV.

This change replaces overloaded EINVAL with ENODEV in a situation
described above for sysfs binary files.
Signed-off-by: NVladimir Zapolskiy <vladimir_zapolskiy@mentor.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>