Provide some hints for the user in case /dev/mem mmap fails

Resolves #121

Corresponding to flashrom svn r385 and coreboot v2 svn r3889.

Signed-off-by: Peter Stuge <peter@stuge.se>
Acked-by: Carl-Daniel Hailfinger <c-d.hailfinger.devel.2006@gmx.net>
1 file changed